A prefix is a bound morpheme that attaches to the beginning of another morpheme. In English, all prefixes are derivational. Derivational prefixes create new words. This page presents an alphabetical list of English prefixes identified through Structured Word Inquiry (SWI), a framework for studying spelling through the meaning, morphology, relatives, and letters/sounds of a word. Each prefix entry includes the denotation (core meaning), etymology (historical origin), and evidence from real words to support the existence of the prefix.
A
a- (Old English prefix denoting (1) “on, in, into, at, engaged in”; (2) “off, from”; (3) reduced form of Old English ge-)
a- (away, from, from off, down, off, away from (denotes disjunction, separation, departure))
a- (to, toward, with regard to, in relation to; sometimes merely emphatic)
a- (copulative prefix denoting “together, with”)
a- (out, away)
ab- (away, from, from off, down, off, away from (denotes disjunction, separation, departure))
abs- (away, from, from off, down, off, away from (denotes disjunction, separation, departure))
ac- (to, toward, with regard to, in relation to; sometimes merely emphatic)
ac- (Old English prefix denoting (1) “on, in, into, at, engaged in”; (2) “off, from”; (3) reduced form of Old English ge-)
ad- (to, toward, with regard to, in relation to; sometimes merely emphatic)
af- (to, toward, with regard to, in relation to; sometimes merely emphatic)
ag- (to, toward, with regard to, in relation to; sometimes merely emphatic)
al- (to, toward, with regard to, in relation to; sometimes merely emphatic)
an- (negating prefix)
an- (to, toward, with regard to, in relation to; sometimes merely emphatic)
an- (up, on, upon, up to, toward, throughout, back, backwards, again, anew)
ana- (up, on, upon, up to, toward, throughout, back, backwards, again, anew)
ant- (against, opposed to, opposite of, instead)
anterio- (before, front)
anti- (against, opposed to, opposite of, instead)
ap- (to, toward, with regard to, in relation to; sometimes merely emphatic)
ap- (of, from, away from, separate, apart from)
apo- (of, from, away from, separate, apart from)
ar- (to, toward, with regard to, in relation to; sometimes merely emphatic)
as- (to, toward, with regard to, in relation to; sometimes merely emphatic)
as- (away, from, from off, down, off, away from (denotes disjunction, separation, departure))
at- (to, toward, with regard to, in relation to; sometimes merely emphatic)
atto- (eighteen)
B
be- (verb and noun prefix, intensive prefix)
C
cac- (bad, ill, poor, evil)
caco- (bad, ill, poor, evil)
cat- (down, downward, with, along, through, on, against, concerning)
cata- (down, downward, with, along, through, on, against, concerning)
cath- (down, downward, with, along, through, on, against, concerning)
cis- (on the same side, on the near side of, on this side)
co- (together, with)
col- (together, with)
com- (together, with)
con- (together, with)
contra- (against, in opposition; in return; corresponding)
contro- (against, in opposition)
cor- (together, with)
coun- (together, with)
D
de- (down, down from, from, off, off, away, from among; through, throughout, in different directions, between; negating prefix, often denoting completely, totally; also often merely intensive, denoting thoroughly, entirely)
demi- (half)
des- (through, throughout, in different directions, between, also often merely intensive, thoroughly, entirely)
des- (chemical prefix denoting the removal of a group from a molecule)
di- (negating prefix denoting “lack of, not, opposite of, apart, away, asunder”)
di- (through, throughout, in different directions, between, also often merely intensive, thoroughly, entirely)
dia- (through, throughout, in different directions, between, also often merely intensive, thoroughly, entirely)
dif- (negating prefix denoting “lack of, not, opposite of, apart, away, asunder”)
dis- (negating prefix denoting “lack of, not, opposite of, apart, away, asunder”)
dys- (difficult, bad, abnormal)
E
e- (out of, up, away, outside, throughout, former, lacking, thoroughly, completed)
e- (prothetic vowel)
e- (reduced form of Old English ge-)
e- (electronic)
ec- (out of, up, away, outside, throughout, former, lacking, thoroughly, completed)
ef- (out of, up, away, outside, throughout, former, lacking, thoroughly, completed)
el- (near, at, in, into on, within)
em- (near, at, in, into on, within; verb prefix)
en- ((1) near, at, in, into on, within; (2) verb prefix)
ep- (on, upon, above, in addition to, toward, among)
epi- (on, upon, above, in addition to, toward, among)
es- (out of, up, away, outside, throughout, former, lacking, thoroughly, completed)
eu- (good, well)
ev- (good, well)
extro- (outside, except, beyond)
F
femto- (fifteen)
for- ((1) out, away, opposite; (2) completely, utterly, to exhaustion or destruction)
fore- (out, away, opposite, completely)
H
hama- (together with)
hemi- (half)
hom- (same, the same, equal, like)
homo- (same, the same, equal, like)
hyp- (under, beneath, less, less than)
hyper- (over, above, beyond, exceedingly, to excess)
hypo- (under, beneath, less, less than)
I
i- (internet)
i- (negating prefix)
ig- (negating prefix)
il- (negating prefix)
il- (preposition denoting “at, on, from, under, during, about, among, to, toward, against, until, about, according to”)
im- (negating prefix)
im- (preposition denoting “at, on, from, under, during, about, among, to, toward, against, until, about, according to”)
in- (negating prefix)
infra- (under, below, beneath)
intel- (between, among, during, betwixt, in the midst of)
intra- (within, inside, on the inside, in, into, during, in the course of)
intro- (in, on the inside, within, to the inside)
ir- (negating prefix)
ir- (preposition denoting “at, on, from, under, during, about, among, to, toward, against, until, about, according to”)
is- (equal, similar, identical, even, level)
iso- (equal, similar, identical, even, level)
M
mes- (bad, wrong)
met- (change, alter, after, behind, among, between, higher, beyond, in the midst of, in common with, by means of, in pursuit or quest of)
meta- (change, alter, after, behind, among, between, higher, beyond, in the midst of, in common with, by means of, in pursuit or quest of)
mete- (in the midst of, among, between)
mis- (bad, wrong, divergent, astray, difference, change, negating prefix)
N
n- (no, not, negative)
ne- (not)
neg- (not)
non- (negating prefix)
O
ob- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
obs- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
oc- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
of- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
op- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
os- (toward, to, against, before, near, across, down, in the direction of, in front of, before, at, upon, about in the way of with regard to, because of; sometimes merely intensive)
P
pan- (all, every, whole)
par- (above, beyond, beside, between, near, across, abnormal, resembling)
para- (above, beyond, beside, between, near, across, abnormal, resembling)
pel- (through, by means of, thoroughly, maximum)
peri- (around, about, enclosing, surrounding, near, during)
peta- (five)
por- (forward, forth, toward the front, beforehand, in advance, taking care of, in place of, on behalf of, before, for, in exchange for, just as, in front of, sooner, in favor of, favoring)
posterio- (after, later, behind)
prae- (before, earlier, in front of)
pre- (before, earlier, in front of)
pro- (forward, forth, toward the front, beforehand, in advance, taking care of, in place of, on behalf of, before, for, in exchange for, just as, in front of, sooner, in favor of, favoring)
pros- (to, toward, before, forward)
pur- (forward, forth, toward the front, beforehand, in advance, taking care of, in place of, on behalf of, before, for, in exchange for, just as, in front of, sooner, in favor of, favoring)
R
re- (back, back from, back to the original place, again, anew, once more; sometimes merely intensive)
red- (back, back from, back to the original place, again, anew, once more)
ren- (back, back from, back to the original place, again, anew, once more)
ri- (back, back from, back to the original place, again, anew, once more; sometimes merely intensive)
S
s- (physics prefix naming subatomic particles with a spin of 0)
se- (without, apart, aside)
sed- (without, apart, aside)
sem- (half, part, imperfect, twice)
sesqui- (one and a half, one half more)
so- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sou- (under, beneath, below)
su- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sub- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
suc- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
suf- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sug- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sum- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sup- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
supr- (above, over, beyond)
supra- (above, over, beyond)
sur- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sur- (over, above, beyond, in addition)
sus- (under, beneath, below, behind, resulting from further division, at the foot of, close to, up to, towards, within, during, subject to, in the power of, a little, somewhat)
sy- ((1) together with, jointly, alike, at the same time; (2) completive or intensive prefix)
syl- ((1) together with, jointly, alike, at the same time; (2) completive or intensive prefix)
sym- ((1) together with, jointly, alike, at the same time; (2) completive or intensive prefix)
syn- ((1) together with, jointly, alike, at the same time; (2) completive or intensive prefix)
T
tebi- (prefix denoting 240)
tra- (across, over, beyond, through, on the other side of, go beyond)
tran- (across, over, beyond, through, on the other side of, go beyond)
trans- (across, over, beyond, through, on the other side of, go beyond)
tres- (across, over, beyond, through, on the other side of, go beyond)
U
u- (not)
un- (negating prefix)
un- (as far as, up to)
ur- (out of, original, earliest, primitive)
Z
zepto- (multiplied by 10−21)
