• antithesis a setting in opposition
• antidote something given against

* apo- [ap- before a vowel or h] from, away from, off, utterly, completely, lack of

• apostate one who stands away (one who renounces a belief)
• aphesis sending off (loss of an initial unaccented vowel)
• apophthegm a speaking away (a terse saying)

* dia-, di- through, across, over, assunder

• diatom cut through (a unicellular alga, having two symmetrical parts)
• diameter a measure through

Be careful not to confuse dia with di- "two" (diode, dimeter, dicotyledon) or dicho- which indicates "division into two parts" (dichotomy) or with Latin dis- "in different directions" (dissect, dismiss).

dys- [Greek, dus-] ill, un-, mis-, difficult, bad

• dysphoria difficult bearing
• dysteleology doctrine of the purposelessness of nature

* ec-, ex- [Greek, ek, ex] out, from, off

• eccrine secreting externally (as sweat glands do)
• eczema result of boiling out (inflammation of the skin)
• exegesis act of leading out (critical explanation)

ecto- [Greek, ekto-] on the outside

ectoderm outer skin

* en-, em- in

• empathy feeling in
• enthusiasm condition of having a god in one ( < en-theos)

enantio- [en- + anti-] opposite

enantiobiosis condition of living in opposition

endo- within, inside, internal

endoscope instrument for observing inside

eso- inward, within

esoteric more inward

exo- outward, external

• exobiology search for and study of extraterrestrial life
• exosphere the outermost part of the atmosphere

* epi- (ep- before a vowel or h) upon, over, at, near

• epicycle an orbit over an orbit
• ephebe at youth (a young man between the ages of eighteen and twenty)
• epexegesis the addition of an explanatory note to a text
• ephemeral lasting for a day (hemera "day")

* eu- (rarely, ev-) well, good

• euphoria good bearing
• eulogy a good word/speech
• evangel the good message

* cata-, cat- [Greek, kata] down, against, completely [opp. ana-]

• catastrophe a turning down
• cathode a road down (a negatively charged electrode)

* meta-, met- among, between, change, behind, later

• metamorphosis the act of changing shape
• metaphysics the things after the physics
• method a going after

palin-, pali- back, again

palindrome a running backword (a word or phrase that reads the same backwards or forwards)

Examples of palindromes :

• ABLE WAS I ERE I SAW ELBA (Napoleon's lament)
• MADAM I'M ADAM
• A MAN A PLAN A CANAL: PANAMA

* para-, par- beside, beyond, near, incorrectly, like

• paradox beyond opinion
• parabiosis state of living beside (fusion of two organisms)
• paraphernalia what is brought besides the dowry (pherne)

* peri- around, about

• perimorph a form around (a mineral that encloses another mineral)
• peripatetic walking around

Do not confuse with the Latin prefix per-, "through".

* pro- before, forward, for

• prologue thing said before
• program something written for

Do not confuse with the Latin prefix pro- "forth, for, forward, instead of, publicly" (proceed, procrastinate, progress, proscribe) or with the Greek prefix pros- "to, toward, besides" (see next), or with the Greek adjective protos "first" (protoplasm, protozoic).

pros- to, toward, besides, in front

• prosody accompanied song > study of metrical systems
• proselyte one who comes to > a new convert
• prosthesis attachment (putting besides)

* syn-, sym-, syl-, sys- [Greek, sun] with, together

• synagogue a bringing together, assembly
• symbiosis a living together
• syllogism the result of reasoning together
• system the result of causing to stand (histanai) together

* hyper- [Greek, huper] above, beyond, exceedingly

• hyperthyroid above the doorlike gland
• hypermetric beyond the meter
• hyperbole a throwing beyond (exaggeration)

* hypo-, hyp- [Greek, hupo] under

• hypotenuse stretching under
• hypodermic under the skin
• hypothesis the act of setting under