Prefixes

a-, an- : not, without, lacking, deficient (an- before a vowel or h)

ab- :away from (a- rarely before certain consonants; abs- before c and t):

ad- (ac- before c; af- before f; ag- before g; al- before l; an- : before n; ap- before p; ar- before r;  as- before s; a- before sp; at- before t): to, toward

ambi-: both

amphi-, ampho-: on both sides, around, both

ana-: up, back, against, throughout

ante-: before, forward

anti- : against, opposed to, preventing, relieving (ant- often before a vowel or h; hyphenated before I)

apo-: away from 

bi- (bin-, bis-): two, twice, double, both 

cata- (cat- before a vowel or h): downward; disordered

circum-: around

con- (co- before h; col- before l; com- before e, m, and p; cor- before r): together, with; thoroughly, very

contra-: against, opposite

de-: down, away from, absent

di- (rarely dis-): two, twice, double

dia- (di- before a vowel): through, across, apart

dis- (di- before g, v, and usually before l; dif- before f ): apart, away

dys-: difficult, painful, defective, abnormal 

e-, ec- (ex- before a vowel): out of, away from

ecto- (ect- often before a vowel): outside of

en- (em- before b, m, and p): in, into, within

endo-, ento- (end-, ent- before a vowel): within

epi- (ep- before a vowel or h): upon, over, above

eso-: within, inner, inward

eu-: good, normal, healthy

ex- (e- before certain consonants; ef- before f ): out of, away from

exo-: outside, from the outside, toward the outside

extra- (rarely extro-): on the outside, beyond

hemi-: half, partial; (often) one side of the body

heter-, hetero-: different, other, relationship to another

homo-, homeo-: same, likeness

hyper-: over, above, excessive, beyond normal

hypo- (hyp- before a vowel or h): under, deficient, below normal

in- :  (il- before l; im- before b, m, and p; ir- before r): in;  not; very, thoroughly

infra-: beneath, below

inter-: between

intra- : within (rarely intro-)

meta- (met- before a vowel or h): change, transformation, after, behind

mono- (mon-before a vowel or h): one, single

mult- (often multi-): many, much, affecting many parts

non-: not

ob- : against, toward; very, thoroughly (oc- before c; op- before p)

para- : alongside, beside, abnormal, beyond (often par- before a vowel)

per- (pel- before l): through; very, thoroughly

peri-: around, surrounding

post-: after, following, behind

pre-: before, in front of

pro-: before; forward, in front

pros-, prosth-: in place of

re-: back, again

retro-: backward, in back, behind

se-: apart, away from

semi-: half

sub- (suf- before f; sup- before p): under

super- (often supra-): over, above; excess

syn- (sym- before b, p, and m; sy- : n assimilates or is dropped before l and s): together, with, joined

trans-: across, through