Hyphenation Notes
HYPHENS (OVERVIEW)
The question: to hyphenate or not to hyphenate? The answer: it depends. The information
provided here is to be used not as rules to be followed dogmatically but as a guide to ensure
accuracy and consistency for cases in which there is doubt.
Nouns
Some nouns are always hyphenated, regardless of function or position:
spin-parity
two-surface
four-velocity
threemomentum
two-spinor
three-vector
two-form
two-plane
Many of these nouns can lead to ambiguity; be careful to distinguish “three-momentum
bins” from “three momentum bins.”
Numbers
Written-out numbers that are two words are not hyphenated unless they are used adjectivally:
twenty-five persons were present
three fourths of the crowd was unruly
Elements
Written-out elements with mass or isotope number following are always hyphenated:
cobalt-60 (or Co60 or 60Co, but not Co-60)
dysprosium-161 nitrogen-14
Compound Nouns
In general, compound nouns such as
buildup
crossover
cutoff
knockout
output
are one word (unhyphenated). The compound verbs from which these nouns are derived are
two words:
We cut off the frequency at ...
Compare
(i) the cutoff frequency
(ii) the cut-off frequency
Case (i) identifies the frequency at which cutoff occurs. Case (ii) identifies a frequency that
has been cut off.
Hyphenation Notes
In general, compound nouns such as
t channel
x ray
δ function
α particle
p type
s wave
are two words. An exception is names of materials:
β-brass, γ-cerium, n-CdTe, o-H2.
Elliptical Forms
The following are examples standard elliptical forms for hyphenated words:
a- and c-axis values
electro- and magneto-optical
even- and odd-parity values
two- or more-term expansion
x(y) stands for high- (low-) energy
scattering
third- and higher-order terms.
These examples are neat and efficient because the words are both normally hyphenated. It is
not correct to artificially add hyphens as in
inter- and intra-atomic (wrong)
auto- and photoionization (wrong)
If a phrase is hyphenated in the following table, hyphenate that phrase when it is used as a unit
modifier (but not necessarily when used as a noun or predicate adjective). Phrases that begin
with a symbol (“s channel”) are entered in the form “s-, t-, u-channel.” An effort has been
made to provide an entry for each of a pair of antonyms (“high-pressure” and “low-pressure”
are separate entries); phrases beginning with numbers, however, have entries only in common
forms (“two-step” is listed, but “three-step” is left to inference). The table has been prepared in
conformity with the rules for hyphenation given above. To judge a hyphen correct or preferred
requires a study of the context in which the hyphen occurs, and therefore no attempt is made
to distinguish correct and preferred hyphens in the table.
The table is not complete; the context in which the phrase occurs may make application of
the rule inadvisable or incorrect. The table should not be used as a substitute for common
sense. HYPHENATION SHOULD BE GOVERNED BY CLARITY AND
MEANING.
Note that phrases shown without hyphens should not be hyphenated. Phrases with en dashes
take en dashes instead of hyphens.
Hyphenation Notes
Guidelines for Unit Modifier Hyphenation: Caution, form depends on meaning!
beta-function
channel: s-, t-. u-channel
above-mentioned
big-bang
channel-mixing
absolute-temperature
binary-alloy
channel-plate
acceptor-pair
binary-encounter
charge-carrier
acoustic(al)-mode
binding-energy
charge-compensated
acoustic(al)-phonon
black-hole
charge-conjugation
air-fired
Bloch-wall
charge-density
air-showered
block-diagonal
charge-exchange
algebra: C*-algebra(ic)
block-spin
charge-sensitive
alkali-metal
blueshifted
charge-transfer
alkaline-earth
body-centered
charged-lepton
all-[any noun]
body-centered-cubic
charged-pion
alternating-gradient
bond-bending
chemical-potential
amorphous-metal
bond-length
chiral-invariant
analog-to-digital
bond-stretching
chiral-symmetric
angle-integrated
boundary-condition
clear-cut (always)
angle-resolved
boundary-value
close-coupling
angular-correlation
bound-electron
closed-channel
•angular momentum
bound-state
closed-form
arc-length
Bragg-peak
closed-loop
arc-melted (always)
branching-ratio
closed-shell
argon-ion
branch-point
close-packed
as-grown
cloud-chamber
brass: α-, β-brass (always)
atom: A-, B-atom
cluster-diagonal
Bridgman-grown
atom-pair
cluster-ion
Brillouin-zone
atomic-orbital
cluster-renormalization
broken-mass
audio-frequency
cluster-variation
broken-SU(3) [“brokenAuger electron
coarse-grained
SU(3) sum rules,” but
axial-vector
coherent-potential
“broken SU(3)
axial-vector-meson
coherent-state
axis: a-, b-, c-axis, x-, y-axis
symmetry”]
coincidence-counting
broken-symmetry
cold-rolled
back-angle
bubble-chamber
cold-trap
backward-scattering
bulk-matter
cold-worked
ball-bearing
bulk-plasmon
collective-mode
band: d-band, X-band; dcolliding-beam
band-width
capillary-wave
complex-angularband-edge
carbon-glass
momentum
bandgap
carrier-concentration
complex-conjugate
band-structure
cathode-ray
complex-frequency
bare-mass
cation-site
complex-Regge-pole
baryon-exchange
center: F-center, U-center,
complex-valued
basis-state
X-center
compound-nuclear
beam-foil
center-of-mass
compound-nucleus
beam-spot
central-atom
computer-simulated
beryllium-base
central-cell
condensed-matter
best-fit(ted)
central-separable-potential
Hyphenation Notes
conduction-band
conduction-electron
configuration-averaged
configuration-interaction
configuration-space
constant-temperature
contact-interaction
continuous-moment
continuous-wave
continuum-orbital
contrast transfer
conversion: k-conversion
coordinate-state
copper-Constantan
core-level
core-polarization
cosmic-ray
Coulomb-corrected
coupled-channel
coupled-mode
coupling-constant
coupling: LS-coupling
critical-field
critical-point
cross-check (always)
cross-coupling
cross-relaxation
cross-section
crossed-beam
crossed-channel
crossing-even
crossing-matrix
crossing-odd
crossing-symmetric
crossing-symmetry
crystal-field
crystal-field-dependent
crystal-field-split(ting)
crystal-growth
cubic-field
current-algebra
current-cavity
current-density
current-temperature
current-voltage
curve-fitting
cut: X-, Y-cut
cycle: m-cycle
dangling-bond
data-acquisition
data-filtering
dead-time
Debye-temperature
decay: α-, β-, γ-decay (but
“α decay rate, “β decay
energy”)
deep-(in)elastic
defect-lattice
deflection-energy
deformation-potential
delay-time
density-fluctuation
density-functional
density-matrix
density-of-states
diamond-anvil
dielectric-response
diffraction-limited
diffusion-limited
dimensional: n-, (n – 1)dimensional
dipole–dipole
direct-channel
direct-gap
direct-interaction
direct-process
direct-scattering
direct-space
direct-transition
discrete-continuum
dispersion-relation
dispersion-theoretic
distorted-wave
distorted-wave Bornapproximation
domain-wall
donor-accepted
donor-electron
doped: p-doped, Nedoped
Doppler-shift(ed)
dotted–dashed
double charge (but
“double-chargeexchange process”)
double-counting
double-differential
double-escape
double-grating
double-ionization
double-isotope-effect
double-logarithmic
double-minimum
double-nested
double-pion
double-pole
double-resonance
double-scattering
double-spectral
double-time
double-well
down-spin
drift-diffusion
dry-ice
dual-beam
dual resonance
dual-symmetric
easy-plane
effective-field
effective-mass
effective-medium
Einstein-oscillator
elastic-scattering
elastic-unitarity
electric dipole
electric field
electric-field-gradient
electric quadrupole
electron: d-, p-electron, Nelectron
electron-beam
electron-capture
electron-density
electron-diffraction
electron-gas
electron–hole
electron-impact
electron-initiated
Hyphenation Notes
electron–ion (–proton,
–phonon, –deuteron,
etc.)
electron-lattice
electron-loss
electron-nuclear
electron-nuclear-doubleresonance
electron-paramagneticresonance
electron-scattering
electron-spin
electron-spin-resonance
electron-transport
electron-tunneling
elementary-particle
embedded-cluster
emission-peak
empty-lattice
empty-target
end-point
energy-band
energy-conserving
energy-gap
energy-integrated
energy-level
energy-loss
energy-momentum
energy-transfer
ensemble-average
equal-composition
equal-energy
equal-mass
equal-phase
equal-time
equal-velocity
equivalent-photon
even–even (always)
even-mass
even-parity
even-shell
even-signature
exact-SU(3) [see “brokenSU(3)”]
exact-symmetry
exchange-correlation
exchange-coupled
exchange-degenerate
exchange-scattering
exchange-split
excited-state
exciton-polariton
external-line
eye-guiding
face-centered
face-centered-cubic
factor: g factor
factor-of-2
fan-out
far-field
far-infrared
far-side
fast-diffusion
fast-logic
Fermi-level
Fermi-liquid
Fermi-surface
fiber-optic
field-emission
field-enhancement
field-ionization
field-theoretic
final-state
fine-structure
finite-dimensional
finite-energy
finite-nuclear-size
finite-size
finite-thickness
finite-volume
first excited
first-order
first-principles
fission-fragment
fission-mass
fixed-point
•flashlamp
•flashlamp-pumped
flat-space
flip-flop
float-zone
flow-point
flow-rate
fluctuating-valence
fluid-dynamical
fluid dynamics
fluid-phase
flux-grown
flux-line
flux-pinning
fly-by
Fock-space
force-constant
form-factor
forward–backward
forward-scattering
four-divergence (always)
fourfold-degenerate
Fourier-analyzed
Fourier-transformed
four-momentum (always)
four-point
four-potential (always)
four-probe (always)
four-quark (always)
four-tensor (always)
four-vector (always)
fractional-charge
fractional-order
free-atom
free-carrier
free-electron
free-energy
free-induction
free-induction-decay
free-surface
freeze-out (always)
frequency-transmission
frozen-core
full-target
function: Λ-, ,-function
functional-integral
fused-quartz
gain–length
gauge-field
gauge-invariant
geometrical-optics
ghost-eliminating
giant-resonance
glide-reflection
Hyphenation Notes
gold-plated
grain-boundary
grain-size
grazing-incidence
Green’s-function
ground-band
ground-based
ground-state
group IIIA
group-theoretic
group-velocity
half- (see p. 21)
Hall-coefficient
Hall-effect
Hall-probe
hard-core
hard-kaon
hard-pion
hard-sphere
harmonic-oscillator
harmonic-vibrator
heat-capacity
heat-exchanger
heat-flow
heat-pulse
heavy-fragment
heavy-hole
heavy-ion
heavy-mass
helicity-(non)flip
hexagonal-close-packed
high-, higher-, highesthigh-concentration
high-conductivity
high-density
high-dose
high-energy (but “high
energy density”—the
density is high)
high-energy-density (when
the whole phrase is a
unit modifier)
high-energy scattering
high-field
high-flux
high-frequency
high-gain
high(er)-lying
high-momentum
high-momentum-transfer
high(er)-order
high-pass
high-precision
high-pressure
high-purity
high-resistivity
high-resolution
high-Rydberg
high-speed
high-symmetry
high-T
high-temperature
high-vacuum
high-voltage
Hilbert-space
hollow-cathode
host-impurity
host-ion
host-lattice
hot-electron
hypernetted-chain
ideal-gas
identical-oscillator
ill-defined
image-source
impact-parameter
impedance-matched
impulse approximation
impurity-associated
impurity-host
impurity-induced
incident-beam
incident-field
incident-particle
incident-proton
incoherent-scattering
independent-particle
indirect-gap
indirect-transition
inelastic-scattering
infinite-dimensional
infinite-momentum
infrared-absorption
infrared-active
infrared-divergent
initial-state
inner-core
inner-shell
in-phase
in-plane
in-state
intermediate-state
intermediate-valence
internal-conversion
internal-symmetry
invariant: CP-, SU(3)invariant
invariant-mass
ion-beam
ion-beam scattering
ion-pair
ion-pumped
irradiated: x-irradiated
Ising-model
isobaric-analog
isobaric-spin
isomer-shift
isospin-(non)conserving
isospin-invariant
isospin-selective
isospin-singlet
isotropic-spin
Josephson-junction
jungle-gym
kinetic-energy
Knight-shift
laboratory-frame
Landau-level
large-angle
laser-induced
lattice-constant
lattice-dynamical
lattice-gas
lattice-parameter
leading s, t
leading-order
leading-trajectory
least-mean-squares
least-squares
Hyphenation Notes
least-squares-fitted
left-hand
Legendre-polynomial
level:
d-, f-, k-, p-, s-level
level-density
light-cone
light-emission
light-fragment
light-mass
light-scattering
line: A-line
linear-chain
linear-expansion
linear-response
line-group
line-narrowing
line-shape
line-shift
Liouville-operator
liquid-crystal (line)
liquid-gas
liquid-4He
liquid-helium
liquid-nitrogen(-cooled)
liquid-vapor
lithium-drifted
local-density
local-field
local-moment
local-orbital
local-order-parameter
lock-in
log-derivative (always)
log–log (always)
long-dashed
long-distance
long-lived
long-range
long-range-order
long-standing
long-time
long-wave(s)
long-wavelength
longitudinal-acoustic
longitudinal-mode
longitudinal-optic
look-up
look-up-table
Lorentz-covariant
low-, lower-, lowestlow-concentration
low-conductivity
low-density
low-(sub)energy
low-field
low-frequency
low-gain
low-light-level
low(er)-lying
low-mass
low-momentum
low-pass
low-pressure
low-resistivity
low-symmetry
low-temperature
low-voltage
low-Z
lower-level
lower-state
lowest-order
magnetic dipole
magnetic field
magnetic-field-dependent
magnetic-flux
magnetic-moment
magnetic quadruple
magnetic-resonance
magnetic-susceptibility
majority-carrier
majority-spin
many-body
many-channel
many-electron
mass-(in)dependent
mass-renormalization
mass-scaling
master-equation
matrix: S-, T-matrix
matrix-isolated
maximum-likelihood
mean-field
mean free
mean-free-path
mean-square (check
context)
meson: K-meson, µ-, πmeson
metal-atom
metal-insulator
methyl-group
methyl-proton
minimal-coupling
minimum-energy
minority-carrier
minority-spin
mirror-symmetry
missing-mass
mixed-crystal
mixed-valence
mixing-chamber
mid E-mode, LO-, TAmode
mode-Grüneisen
mode-locked
model-specific
molecular-beam
molecular-dynamics
molecular-field
molecular-orbital
molecule–ion
momentum-conserving
momentum-transfer
Monte Carlo
Monte Carlo-predicted
Mössbauer-effect
muffin-tin
muffin-tin-potential
multiple-event
multiple-ionization
multiple-parameter
multiple-pulse
multiple-regression
multiple-scattering
multiple-splitting
multiplet: SU(3)-multiplet
•narrowband
narrow-width
natural-parity
near-diffraction-limited
Hyphenation Notes
near-edge
near-field
nearest-neighbor
near-identity
near-infrared
nearly-free-electron
near-side
near-ultraviolet
negative-energy
negative-ion
negative-parity
negative-signature
nematic-isotropic
neutral-density
neutral-donor
neutron-diffraction
neutron-diffraction
scattering
neutron-scattering
next-higher
next-nearest
next-nearest-neighbor
noble-metal
noise-immune
nonlinear optical
nonsense-choosing
normal-dispersion
normal-emission
normal-fluid
normal-incidence
normal-metal
normal-mode
normal-state
nuclear-bar
nuclear-magneticresonance
nuclear-spin
nucleon-nucleus
null-plane
number: c-number
occupation-level
odd-A
odd–even
odd-mass
odd–odd (always)
odd-parity
odd-shell
odd-signature
odd-symmetry
off-axis
off-(the-)energy-shell
off-(the-)mass-shell
off-shell
on-axis
once-subtracted
one-component
one-constraint
one-electron
one-loop
one-parameter
one-particle
one-photon
one-pion
one-pion-exchange
on-shell
on-(the-)energy-shell
on-(the-)mass-shell
open-channel
open-orbit
optical-absorption
optical-density
optical-field
optic(al)-mode
optical-model
optic(al)-phonon
orbital-mixing
ordered-phase
order-of-magnitude
order-parameter
ortho-concentration
orthogonalized-planewave
ortho–para (always)
osmotic-pressure
outer-shell
out-of-phase
out-of-plane
out-state
pair-correlation
pair-counting
pair-creation
pair-production
parallel-plate
parallel-shift
para-molecule
para-state
parity-doubled
parity-partner
parity-symmetric
parity-symmetric
parity-violating
partial-wave
particle: α-, β-, γ-particle
particle-bound
particle–hole
particle-identification
path-integral
path-length
Pauli matrix
Pauli spin
perfect-crystal
period-doubling
perturbation-theory
phase: d-phase, α-, β-, γphase
phase-coherent
phase-conjugate
phase-detected
phased-array
phase-locked
phase-matched
phase-sensitive
phase-separation
phase-shift
phase-space
phase-transition
phonon-assisted
phonon-dispersion
phonon-polariton
phonon-scattering
photon-counting
physical scattering
pion-decay
pion-pair
pion-scattering
plane: a-, b-, c-plane, kplane, x-, y-, z-plane
plane-parallel
plane-polarized
plane-wave
plano–concave
Hyphenation Notes
plasma-wave
plasmon-polariton
point: N-point
point-charge
point-contact
point-dipole
point-group
point-ion
point-nucleus
point-source
Poisson-sum
polarization-sensitive
polarized: p-, s-polarized
polar optical
polar-phonon
pole-dominance
porous-membrane
positive-definite
positive-energy
positive-ion
positive-parity
positive-signature
positron annihilation
potential-energy
potential-well
powder-diffraction
power-density
power-law
power-series
pressure-effect
principal-axis
principal-value
probe-laser
prong: one-, two-prong
(always)
proton-scattering
proximity-effect
pseudoscalar-meson
pulse-height
pulse-modulated
pulse-shape
pure: 99%-pure, 99%purity
quadrupole-split
quantum-defect
quantum-field-theory
quantum-mechanical
quantum-percolation
quantum scattering
quarter-point
quarter-wave
quartz-crystal
quasiquasi-one-dimensional
(always)
quasi-static-limit
radial wave
Raman-active
Raman-scattered
Raman-scattering
random-alloy
random-cluster
random-dot
random-field
random-phase
random-phaseapproximation
random-walk
rare-earth
rare-gas
ray: x-ray. α-, β-, γ-ray, xray absorption, x-ray
emission
reaction-rate
readout
real-potential
real-space
real well (“real well
depth”)
reciprocal-lattice
redshifted
•refractive index
Regge-pole
Regge-trajectory
relaxation-time
renormalization-group
repulsive-core
resonance scattering
resonant-cavity
resonant-level
rest-frame
right-angle
right-hand
rigid-band
rigid-ion
rigid-lattice
rigid-rotor
rise-time
rod-shaped
room-temperature
root-mean-square
rotating-drum
rotating-frame
saddle-point
scalar-meson
scale-invariance
scale-invariance-breaking
scattered-neutron
Schmid-circle
second-harmonic
second-nearest
second-nearest-neighbor
second-neighbor
second-quantized
second-rank
second-sound
secondary-emission
secondary-ion
selfself-consistent-field
self-phase
sense-choosing
series-expansion
shallow-impurity
shell: d-, p-, s-shell, K-, L-,
M-shell, s–d-shell
shell-model
short-dashed
short-distance
short-lived
short-range
short-range-order
short-time
short-wavelength
shot-noise
shower-counter
signal-averaging
signal-to-noise
signal-averaging
signal-to-noise
simple cubic
sine-Gordon
Hyphenation Notes
single-channel
single-component
single-crystal
single-ion
single-ionization
single-line
single-mode
single-particle
single-photon
single-pion
single-quantum
single-scattering
single-site
single-step
single-stranded
single-value(d)
site-adsorption
site-diagonal
site-occupation
slow-diffusion
slow-jump
small-angle
small-signal
smectic-A, -B
so-called
soft-mode
soft-pion
soft-x-ray
solgel
solid-body
solid-state
soliton-magnon
space-charge
space-fixed
space-group
space-orbital
space-spin
space–time
spark-chamber
spatial-averaging
spatial-frequency
special-relativistic
specific-heat
spectral-function
spin-aligned
spin-allowed
spin-configuration
spin-correlated
spin-density
spin-diffusion
spin-down
spin-echo
spin-exchange
spin-flip
spin-flop
spin-fluctuation
spin-forbidden
spin-glass
spin-Hamiltonian
spin-lattice
spin-one (-1)
spin-orbit
spin-orbital (always)
spin-other-orbit (always)
spin-pair
spin-parity (always)
spin-polarization
spin-quantization
spin-relaxation
spin-resonance
spin-reverse
spin–spin (always)
spin-symmetric
spin-up
spin-wave
spin-zero (-0)
split-band
split-pole
spot-welded (always)
spring-loaded
sputter-deposited
square-integrable
square-law
square-root
square-wave
square-well
square-steel
stainless-steel
standard-cell
standing-wave
state: d-, f-, k-, p-, s-state
state-density
stationary-state
statistical-mechanics
statistical-model
steady-state
steepest-descent
step-by-step
step-function
step-up
stimulated-echo
Stokes-scattered
Stokes-scattering
stopping-power
straight-line
strangeness-changing
strange-particle
stray-light
stress-energy
stress-induced
strip-chart
strong-coupling
strong-field
strong-interaction
strong-mode
structure-function
sum: f-, s-sum; f-sum-rule
sum-rule
sum-frequency
sunphotometer
surface-atom
surface-barrier
surface-cluster
surface normal
surface-plasmon-polariton
(the noun is surface
plasmon polariton)
surface-potential
surface-profile
surface-roughening
surface-state
surface-tension
surface-to-volume
switch: Q-switch(ed)
symmetric-top
symmetry: SU(3)symmetry; SU(3)symmetric
symmetry-breaking
synchrotron-radiation
target-foil
Taylor-series
Hyphenation Notes
temperature(in)dependent
temperature-scaling
thermal-conductivity
thermal-desorption
thermal-expansion
thermal-neutron
thick-target
thin-film
third-sound
three-momentum (always)
through-space
tight-binding
time-average(d)
time–bandwidth
time correlation
time-of-flight
time-ordered
time-ordering
time-reversal
time-shifted
total-cross-section
total-energy
transfer-matrix
transform-limited
transition-metal
transition-probability
transit-time
transerve-acoustic
transverse-mode
transverse-optic(al)
traveling-cluster
traveling-wave
tree-graph
trial-wave-function
turn-on
two-body
two-boson
two-center
two-compound
two-dimensional
two-particle
two-prong (always)
two-quark (always)
two-step
two-time
twofold-degenerate
twofold-symmetry
type: n-, p-type, A-type,
type IIIA, type II
uniform-precession
unitary-spin
unitary-(anti)symmetric
unit-cell
up-spin
upper-level
upper-state
vacuum-deposited
vacuum-ultraviolet
valence-band
valence-excited
valley-orbit
variable-temperature
vector: n-vector (always)
vector-meson
very-long-baseline
virtual-crystal
virtual-phonon
virtual-photon
visible-light
volume-integral
volume-plasmon
water-cooled
wave: d-, p-, s-wave
•wavefront
wave-function
•wavenumber
wave-packet
wave-vector(-space)
weak-anisotropy
weak-coupling
weak-electromagnetic
weak-field
weak-interaction
weak-localization
weak-mode
weak-radiative
weight-gain
well-known
wetting-layer
white-light
white-noise
Wick-rotated
work-function
world-scalar
wrong-signature
wurtzite-structure
x-ray-absorption
x-ray-diffraction
Yukawa-potential
zero-bias
zero-field
zero-frequency
zero-gradient
zero-mass
zero-momentum
zero-momentum-transfer
zero-order
zero-phonon
zero-point
zero-prong (always)
zero-shift
zero-spin
zero-temperature
zeroth-order
zinc-blende
zone-boundary
zone-center
zone-edge
zone-refined