Etymology
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tetra- 
before vowels tetr-, word-forming element meaning "four," from Greek tetra-, combining form of tettares (Attic), tessares "the numeral four" (from PIE root *kwetwer- "four").
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glotto- 

word-forming element meaning "language," from Attic Greek glōtto-, from glōtta, variant of glōssa "tongue; language" (see gloss (n.2)).

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thalasso- 

before vowels thalass-, word-forming element meaning "sea, the sea," from Greek thalassa "the sea" (in Homer, when used of a particular sea, "the Mediterranean," as opposed to ōkeanos), a word from the Pre-Greek substrate language. In Attic Greek thalatta, hence sometimes thalatto-.

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micro- 

word-forming element meaning "small in size or extent, microscopic; magnifying;" in science indicating a unit one millionth of the unit it is prefixed to; from Latinized form of mikros, Attic form of Greek smikros "small, little, petty, trivial, slight," perhaps from PIE *smika, from root *smik- "small" (source also of Old High German smahi "littleness"), but Beekes thinks it a Pre-Greek word.

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pneumo- 

before vowels pneum-, word-forming element meaning "lung," from Greek pneumōn "lung," altered (probably by influence of pnein "to breathe") from pleumōn (which was an alternative form in Attic), literally "floater," probably cognate with Latin pulmo "lung(s)," from PIE root *pleu- "to flow." The notion perhaps is from the fact that, when thrown into a pot of water, lungs of a slaughtered animal float, while the heart, liver, etc., do not (compare Middle English lights "the lungs," literally "the light (in weight) organs").  

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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 ops (genitive opos) "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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