ENGLISH -- WORD ROOTS & PREFIXES

Word Roots and Prefixes

This list contains some of the common roots and prefixes that make up the building blocks of numerous English words. Following the table of general roots and prefixes is a table of number prefixes.
 

How Words Work

Many words are made up of a root (or base word) and a prefix. Some words also have a suffix. For example, the root word port means to carry or to bear. Attach the prefix ex, meaning out or out of, and you have the word export, to carry out. Attach the prefix im, meaning in or into and you have import, to carry in. Attach the prefix trans, meaning across, and you have transport, meaning to carry across. Now let's attach the suffix able, meaning able to be, and you have importable, exportable, and transportable.

The very words prefix and suffix are good examples, too. Pre means before and fix means to fasten or attach, so quite literally, a prefix is something attached to the beginning of something else. Suf is a variant of sub, below or under, so a suffix is something fastened underneath something else (in this case, behind the root).
By learning the common roots and prefixes (and a few suffixes) you will be able to discern the meaning of many new words almost immediately. (But do look them up for confirmation.) Take the word abject, for example. If you know that ab means away or down and ject means to throw, you can easily figure out that abject doesn't mean something happy. Rather abject's root meaning of thrown down is quite close to the dictionary defintion of cast down in spirit or sunk into depression.
Now that you have learned that ject means to throw, think how many words you can define almost immediately: reject, project, inject, subject, eject, and so on. Roots are a real key to understanding the meaning of new words you come across in your reading.
Note that some modern words are formed by using abbreviated forms of other words. Thus, we see the use of the letter i for Internet in iPhone, iPod, and iTunes, indicating that these items or services work with the Internet. Similarly, the use of e for electronic appears in words such as elearning (and various forms: eLearning, E-Learning, and so on), e-commerce, and e-business. The "e-terms" seem to have been coined before the "i-terms" became popular. And note that most of the "i-terms" are trademarks, while the others are general descriptors: "I'm going to download some iTunes from Apple's e-commerce site because I love e-music." At any rate, these abbreviated forms are not traditional prefixes, but because they are indeed attached to the front of what amounts to root words, they could be considered functional prefixes.

General Roots and Prefixes

Root or Prefix	Meaning	Examples
a, an	not, without	atheist, anarchy, anonymous apathy, aphasia, anemia, atypical, anesthesia
ab	away, down, from, off	absent, abduction, aberrant, abstemious, abnormal, abstract, absorb
acro	high, tip, top	acrobat, acrophobia, acronym, acromegaly, acropolis
act	do, move	action, react, transaction, proactive, activity, activation, deactivate
ad	to, toward	admit, addition, advertisement, adherent, admonish, address, adhesive, adept, adjust
alt	high	altitude, altimeter, alto, contralto, altocumulus, exalt
ambul	to walk	ambulatory, amble, ambulance, somnambulist, perambulate, preamble
anima	soul, life	animation, inanimate, animal, anime, equanimity, animism, animus
ante	before	anteroom, antebellum, antedate antecedent, antediluvian
anti, ant	against, opposite	antisocial, antiseptic, antithesis, antibody, antichrist, antinomies, antifreeze, antipathy, antigen, antibiotic, antidote, antifungal, antidepressant
arm	weapon	army, armament, disarm, rearm, armistice, armor, armory, arms
audi	to hear	audience, auditory, audible, auditorium, audiovisual, audition, audiobook
auto	self	automobile, automatic, autograph, autonomous, autoimmune, autopilot, autobiography
be	thoroughly	bedecked, besmirch, besprinkled, begrudge, begrime, belie, bemoan
bell	war	belligerent, antebellum, bellicose, rebel
bene	good, well	benefactor, beneficial, benevolent, benediction, beneficiary, benefit
bi	two	bicycle, bifocals, biceps, billion, binary, bivalve, bimonthly, bigamy, bimetal, biathlete, bicarbonate
bio	life, living	biology, biography, biodiversity, bioavailability, bioflavonoid, biofuel, biohazard, biomass, biorhythm
cede, ceed, cess	to go, to yield	succeed, proceed, precede, recede, secession, exceed, succession, excess
chron	time	chronology, chronic, chronicle, chronometer, anachronism
cide, cis	to kill, to cut	fratricide, suicide, incision, excision, circumcision, precise, concise, precision, homicide, genocide, regicide
circum	around	circumnavigate, circumflex, circumstance, circumcision, circumference, circumorbital, circumlocution, circumvent, circumscribe, circulatory
clud, clus claus	to close	include, exclude, clause, claustrophobia, enclose, exclusive, reclusive, conclude, preclude
con, com	with, together	convene, compress, contemporary, converge, compact, confluence, concatenate, conjoin, combine, convert, compatible, consequence, contract
contra, counter	against, opposite	contradict, counteract, contravene, contrary, counterspy, contrapuntal, contraband, contraception, contrast, controversy, counterfeit, counterclaim, counterargument, counterclaim, counterpoint, counterrevolution
cred	to believe	credo, credible, credence, credit, credential, credulity, incredulous, creed, incredible
commun	to share	commune, community, communism, communicable, communication, commonality, incommunicado
cycl	circle, wheel	bicycle, cyclical, cycle, encliclical, motorcycle, tricycle, cyclone

General Roots and Prefixes (continued)

Root or Prefix	Meaning	Examples
de	from, down, away	detach, deploy, derange, deodorize, devoid, deflate, degenerate, deice, descend, derail, depress, depart, decompose, destruction
dei, div	God, god	divinity, divine, deity, divination, deify, deism
demo	people	democracy, demagogue, epidemic, demographic, endemic
dia	through, across, between	diameter, diagonal, dialogue, dialect, dialectic, diagnosis, diachronic, diagram, diaphragm, dialysis, diarrhea
dict	speak	predict, verdict, malediction, dictionary, dictate, dictum, diction, indict, contradict
dis, dys, dif	away, not, negative	dismiss, differ, disallow, disperse, dissuade, disconnect, dysfunction, disproportion, disrespect, distemper, distaste, disarray, dyslexia
duc, duct	to lead, pull	produce, abduct, product, transducer, viaduct, aqueduct, induct, deduct, reduce, induce
dyn, dyna	power	dynamic, dynamometer, heterodyne, dynamite, dynamo, dynasty
ecto	outside, external	ectomorph, ectoderm, ectoplasm, ectopic, ectothermal
endo	inside, within	endotoxin, endoscope, endogenous
equi	equal	equidistant, equilateral, equilibrium, equinox, equitable, equation, equator
e, ex	out, away, from	emit, expulsion, exhale, exit, express, exclusive, enervate, exceed, explosion, eject, exude
eu	good, pleasant	euphoria, euphemism, eustress, euphonic, eukaryote
exter, extra	outside of	external, extrinsic, exterior, extraordinary, extrabiblical, extracurricular, extrapolate, extraneous, exterminator, extract, extradite, extraterrestrial, extrasensory, extravagant, extreme
flu, flux	flow	effluence, influence, effluvium, fluctuate, confluence, reflux, influx
flect, flex	to bend	flexible, reflection, deflect, circumflex, inflection, reflex
graph, gram	to write	polygraph, grammar, biography, graphite, telegram, autograph, lithograph, historiography, graphic, electrocardiogram, monogram
hetero	other	heterodox, heterogeneous, heterosexual, heterodyne
homo	same	homogenized, homosexual, homonym, homophone
hyper	over, above	hyperactive, hypertensive, hyperbolic, hypersensitive, hyperventilate, hyperkinetic, hyperlink, hypertext, hypersonic, hypertrophy
hypo	below, less than	hypotension, hypodermic, hypoglycemia, hypoallergenic, hypothermia, hypothesis

General Roots and Prefixes (continued)

in, im	not	inviolate, innocuous, intractable, innocent, impregnable, impossible, incapable, incoherent, impassible, impotent
infra	beneath	infrared, infrastructure, infrasonic
inter, intro	between	international, intercept, intermission, interoffice, internal, intermittent, introvert, introduce
intra	within, into	intranet, intracranial, intravenous, intramural, intramuscular, intraocular
jac, ject	to throw	reject, eject, project, trajectory, interject, dejected, inject, ejaculate
log, logo, loc, loq	word, speech, speak	monologue, dialogue, locution, colloquial, elocution, soliloquy, ventriloquist, apology, doxology, epilogue, logic, eulogy, loquacious
mal	bad, badly	malformation, maladjusted, dismal, malady, malcontent, malfeasance, maleficent, malevolent, malice, malaria, malfunction, malignant
mega	great, million	megaphone, megalomaniac, megabyte, megalopolis, acromegaly
meso	middle	mesomorph, mesoamerica, mesosphere
meta	beyond, change	metaphor, metamorphosis, metabolism, metahistorical, metainformation, metacognitive, metaphysics
meter	measure	perimeter, micrometer, ammeter, multimeter, altimeter, geometry, kilometer
micro	small	microscope, microprocessor, microfiche, micrometer, micrograph
mis	bad, badly	misinform, misinterpret, mispronounce, misnomer, mistake, misogynist, mistrial, misadventure, misanthrope, misread
mit, miss	to send	transmit, permit, missile, missionary, remit, admit, missive, mission
morph	shape	polymorphic, morpheme, amorphous, metamorphosis, morphology, morphing
multi	many	multitude, multipartite, multiply, multipurpose, multicolored, multimedia, multinational
neo	new	neologism, neonate, neoclassic, neophyte
non	not	nonferrous, nonabrasive, nondescript, nonfat, nonfiction, nonprofit, nonsense, nonentity
omni	all	omnipotent, omnivorous, omniscient, omnibus, omnirange, omnipresent
pan	all, whole, general, completely	pantheism, pandemic, panacea, panoply, pan-American, panchromatic, pandemonium, panorama
para	beside	paraprofessional, paramedic, paraphrase, parachute, paralegal, parallel, comparison
per	through, intensive	permit, perspire, perforate, persuade, perceive, perfect, permit, perform, pervasive
peri	around	periscope, perimeter, perigee, periodontal, pericope
phon	sound	telephone, phonics, phonograph, phonetic, homophone, microphone
phot	light	photograph, photosynthesis, photon
poly	many	polytheist, polygon, polygamy, polymorphous
port	to carry	porter, portable, report, transportation, deport, import, export

General Roots and Prefixes

Root or Prefix	Meaning	Examples
re	back, again	report, realign, retract, revise, regain, reflect, rename, restate, recombine, recalculate, redo
retro	backwards	retrorocket, retrospect, retrogression, retroactive
sanct	holy	sanctify, sanctuary, sanction, sanctimonious, sacrosanct
scrib, script	to write	inscription, prescribe, proscribe, manuscript, conscript, scribble, scribe, postscript, transcript
sect, sec	cut	intersect, transect, dissect, secant, section
semi	half	semifinal, semiconscious, semiannual, semimonthly, semicircle
spect	to look	inspect, spectator, circumspect, retrospect, prospect, spectacle
sub	under, below	submerge, submarine, substandard, subnormal, subvert, subdivision, submersible, submit
super, supra	above	superior, suprarenal, superscript, supernatural, supercede, superficial, superhero, superimpose
syn	together	synthesis, synchronous, syndicate, synergy, snyopsis, syncretism
tele	distance, from afar	television, telephone, telegraph, telemetry, telepathy, teleconference
theo, the	God	theology, theist, polytheist, pantheism, atheist, monotheist, theophany
therm, thermo	heat	thermal, thermometer, thermocouple, thermodynamic, thermoelectric
tract	to drag, draw	attract, tractor, traction, extract, retract, protract, detract, subtract, contract, intractable
trans	across	transoceanic, transmit, transport, transducer, transit, intransitive
un	not	uncooked, unharmed, unintended, unhappy, unenlightened, unremarkable
veh, vect, vey	to carry	vector, vehicle, convection, vehement, convey, conveyance, conveyor
vert, vers	to turn	convert, revert, advertise, versatile, vertigo, invert, reversion, extravert, introvert
ven, vent	to come	convention, prevent, intervention, convent, Advent, invent, inventory
verm	worm	vermin, vermicelli, vermiculite, vermicide, vermiform, vermilion
vita	life	vital, vitality, vitamins, revitalize
vol	to will	benevolent, volition, voluntary, malevolent

Number Prefixes

Prefix	Meaning	Examples
mono, uni	one	monopoly, monotype, monologue, mononucleosis, monorail, monotheist, unilateral, universal, unity, unanimous, uniform
bi, di	two	divide, diverge, diglycerides, bifurcate, biweekly, bivalve, biannual, billion
tri	three	triangle, trinity, trilateral, triumvirate, tribune, trilogy, tricycle, trillion
quat, quad	four	quadrangle, quadruplets, quaternary, quarter, quadrillion
quint, penta	five	quintet, quintuplets, pentagon, pentane, pentameter, quintillion
hex, ses, sex	six	hexagon, hexameter, sestet, sextuplets, sextillion
sept	seven	septet, septennial, septillion, September
oct	eight	octopus, octagon, octogenarian, octave, octillion, October
non	nine	nonagon, nonagenarian, nonillion
dec	ten	decimal, decade, decalogue, decimate, decillion, December
cent	hundred	centennial, century, centipede, centillion
mill, kilo	thousand (10^3)	millennium, kilobyte, kiloton
mega	million (10^6)	megabyte, megaton, megaflop, megawatt
giga	billion (10^9)	gigabyte, gigaflop, gigahertz, gigawatt
tera	trillion (10^12)	terabyte, teraflop, terawatt
peta	quadrillion (10^15)	petabyte
exa	quintillion (10^18)	exabyte
zetta	sextillion (10^21)	zettabyte
yotta	septilion (10^24)	yottabyte
milli	thousandth (10^-3)	millisecond, milligram, millivolt, milliwatt, millimeter, millipede
micro	millionth (10^-6)	microgram, microvolt, microwave, microsecond
nano	billionth (10^-9)	nanosecond, nanobucks, nanofarad, nanometer, nanomachine, nanotube, nanotechnology, nanogram, nanoscale
pico	trillionth (10^-12)	picofarad, picocurie, picogram, picomole, picosecond
femto	quadrillionth (10^-15)	femtosecond
atto	quintillionth (10^-18)	attosecond, attometer
zepto	sextillionth (10^-21)	zeptosecond
yocto	septillionth (10^-24)	yoctosecond