Etymology
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epi- 

before vowels reduced to ep-, before aspirated vowels eph-, word-forming element meaning "on, upon, above," also "in addition to; toward, among," from Greek epi "upon, at, close upon (in space or time), on the occasion of, in addition," also "after," from PIE *epi, *opi "near, at, against" (source also of Sanskrit api "also, besides;" Avestan aipi "also, to, toward;" Armenian ev "also, and;" Latin ob "toward, against, in the way of;" Oscan op, Greek opi- "behind;" Hittite appizzis "younger;" Lithuanian ap- "about, near;" Old Church Slavonic ob "on"). A productive prefix in Greek; also used in modern scientific compounds (such as epicenter).

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ana- 

before vowels an-, word-forming element meaning: 1. "upward, up in place or time," 2. "back, backward, against," 3. "again, anew," from Greek ana (prep.) "up, on, upon; up to, toward; throughout; back, backwards; again, anew," from an extended form of PIE root *an- (1) "on, upon, above" (see on, which is the English cognate). In old medical prescriptions, ana by itself meant "an equal quantity of each."

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ob- 

word-forming element meaning "toward; against; before; near; across; down," also used as an intensive, from Latin ob (prep.) "in the direction of, in front of, before; toward, to, at, upon, about; in the way of; with regard to, because of," from PIE root *epi, also *opi "near, against" (see epi-).

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bene- 
sometimes beni-, word-forming element meaning "well," from Latin bene (adv.) "well, in the right way, honorably, properly," from PIE *dwenelo-, suffixed (adverbial) form of root *deu- (2) "to do, perform; show favor, revere." Opposed to mal-. From the same source come Latin bonus "good," bellus "handsome, fine, pretty," and possibly beatus "blessed," beare "to make blessed."
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-cracy 
word-forming element forming nouns meaning "rule or government by," from French -cratie or directly from Medieval Latin -cratia, from Greek -kratia "power, might; rule, sway; power over; a power, authority," from kratos "strength," from PIE *kre-tes- "power, strength," suffixed form of root *kar- "hard." The connective -o- has come to be viewed as part of it. Productive in English from c. 1800.
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piezo- 

word-forming element meaning "pressure," from Greek piezein "to press tight, squeeze," from PIE *pisedyo- "to sit upon" (source also of Sanskrit pidayati "presses, oppresses"), from *pi "on," short for *epi (see epi-) + root *sed- (1) "to sit." First in piezometer (1820), an instrument for ascertaining or testing pressure. It was in common use in word formation from c. 1900.

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presby- 

word-forming element meaning "old," from Greek presby-, combining form of presbys "elderly, aged," as a noun, "elder, old man," which is of uncertain and much debated origin and phonetic development (some Doric forms have -g- in place of -b-). The first element is likely *pres- "before, in front" (from PIE root *per- (1) "forward," hence "in front of, before, first"). Perhaps the whole originally meant "one who leads the cattle," from the root of bous "cow." Watkins, however, has it from PIE *pres-gwu- "going before," with second element from root *gw-u- "going," a suffixed form of root *gwa- "to come."

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anthropo- 

before a vowel, anthrop-, word-forming element meaning "pertaining to man or human beings," from Greek anthrōpos "man; human being" (including women), as opposed to the gods, from andra (genitive andros), Attic form of Greek anēr "man" (as opposed to a woman, a god, or a boy), from PIE root *ner- (2) "man," also "vigorous, vital, strong."

Anthropos sometimes is explained as a compound of anēr and ōps (genitive ōpos) "eye, face;" so literally "he who has the face of a man." The change of -d- to -th- is difficult to explain; perhaps it is from some lost dialectal variant, or the mistaken belief that there was an aspiration sign over the vowel in the second element (as though *-dhropo-), which mistake might have come about by influence of common verbs such as horao "to see." But Beekes writes, "As no IE explanation has been found, the word is probably of substrate origin."

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sch 

consonant cluster that can represent five distinct sounds in English; it first was used by Middle English writers to render Old English sc-, a sound now generally pronounced (and spelled) "-sh-." Sometimes it was miswritten for ch. It also was taken in from German (schnapps) and Yiddish (schlemiel). In words derived from classical languages (school (n.1)), it represents Latin sch-, Greek skh-, but in some of these words the spelling is a restoration and the pronunciation does not follow it (as in schism; Middle English sisme, cisme).

The Yiddish words with it, often derisive or dismissive, tended to come into 20c. American English. In addition to those with entries here, Saul Bellow used schmegeggy, "Portnoy's Complaint" has schmatte "a ragged garment;" schmeck "a sniff" figures in heroin jargon, and schmutz "dirt, filth" has been used. Directly to English from German also are some specialized words: Schmelz "enamel," schmerz "grief, pain, sorrow," 

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a- (1)

prefix or inseparable particle, a conglomerate of various Germanic and Latin elements.

In words derived from Old English, it commonly represents Old English an "on, in, into" (see on (prep.)), as in alive, above, asleep, aback, abroad, afoot, ashore, ahead, abed, aside, obsolete arank "in rank and file," etc., forming adjectives and adverbs from nouns, with the notion "in, at; engaged in." In this use it is identical to a (2).

It also can represent Middle English of (prep.) "off, from," as in anew, afresh, akin, abreast. Or it can be a reduced form of the Old English past participle prefix ge-, as in aware.

Or it can be the Old English intensive a-, originally ar- (cognate with German er- and probably implying originally "motion away from"), as in abide, arise, awake, ashamed, marking a verb as momentary, a single event. Such words sometimes were refashioned in early modern English as though the prefix were Latin (accursed, allay, affright are examples).

In words from Romanic languages, often it represents reduced forms of Latin ad "to, toward; for" (see ad-), or ab "from, away, off" (see ab-); both of which by about 7c. had been reduced to a in the ancestor of Old French. In a few cases it represents Latin ex.

[I]t naturally happened that all these a- prefixes were at length confusedly lumped together in idea, and the resultant a- looked upon as vaguely intensive, rhetorical, euphonic, or even archaic, and wholly otiose. [OED]
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