Etymology
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self- 

word forming element indicating "oneself," also "automatic," from Old English use of self (pron.) in compounds, such as selfbana "suicide," selflice "self-love, pride, vanity, egotism," selfwill "free will." Middle English had self-witte "one's own knowledge and intelligence" (early 15c.).

OED counts 13 such compounds in Old English. Middle English Compendium lists four, counting the self-will group as a whole. It re-emerges as a living word-forming element mid-16c., "probably to a great extent by imitation or reminiscence of Greek compounds in (auto-)," and formed a great many words in the pamphlet disputes of the 17c.

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aero- 

word-forming element meaning "air, atmosphere; gases," in 20c. use with reference to aircraft or aviation, from Greek aēr (genitive aeros) "air, lower atmosphere" (see air (n.1)).

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mammo- 

word-forming element meaning "breast," from Latin mamma "breast" (which is cognate with mamma). The form mammato-, used in cloud terminology in reference to smooth, rounded shapes, is from Latin mammatus.

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ideo- 
word-forming element variously used with reference to images or to ideas, from Greek idea "form; the look of a thing; a kind, sort, nature; mode, fashion," in logic, "a class, kind, sort, species" (see idea).
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rheo- 

word-forming element meaning "current of a stream," but from late 19c. typically in reference to the flow or adjustment of electric current, from Greek rheos "a flowing, stream, current," which is related to rhein "to flow," rhythmos "rhythm" (from PIE root *sreu- "to flow").

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mixo- 

word-forming element of Greek origin meaning "mixed," from Greek mixo-, from mixis "a mixing, mingling, intercourse," from root of mignynai "to mix, mix up, mingle" (from PIE root *meik- "to mix"). As in mixolydian in reference to a half-Lydian mode in ancient Greek music.

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proto- 

before vowels prot-, word-forming element in compounds of Greek origin meaning "first, source, parent, preceding, earliest form, original, basic," from Greek prōto-, from prōtos "first" (from PIE *pre-, from root *per- (1) "forward," hence "before, first"). It is also used in forming words in the sciences and to form compounds having historical reference (such as Proto-Indo-European).

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gluco- 

before vowels, gluc-, word-forming element used since c. 1880s, a later form of glyco-, from Greek glykys "sweet," figuratively "delightful; dear; simple, silly," from *glku-, a dissimilation in Greek from PIE root *dlk-u- "sweet" (source also of Latin dulcis). De Vaan writes that "It is likely that we are dealing with a common borrowing from an unknown source." Now usually with reference to glucose.

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cis- 

word-forming element meaning "on the near side of, on this side," from Latin preposition cis "on this side" (in reference to place or time), related to citra (adv.) "on this side," from PIE *ki-s, suffixed form of root *ko-, the stem of demonstrative pronoun meaning "this." Opposed to trans- or ultra-. Originally only of place, sometimes 19c. of time; 21c. of life situations (such as cis-gender, which is attested by 2011).

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ab- 
word-forming element meaning "away, from, from off, down," denoting disjunction, separation, departure; from Latin ab (prep.) "off, away from" in reference to space or distance, also of time, from PIE root *apo- "off, away" (also the source of Greek apo "off, away from, from," Sanskrit apa "away from," Gothic af, English of, off; see apo-).

The Latin word also denoted "agency by; source, origin; relation to, in consequence of." Since classical times usually reduced to a- before -m-, -p-, or -v-; typically abs- before -c-, -q-, or -t-.
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