Micronesia

1758, Latinization of French polynésie, coined 1756 by French writer Charles de Brosses (1709-1777) in "Histoire des navigations aux terres australes, contenant ce que l'on sait des moeurs et des productions des contrées découvertes jusqu'à ce jour" (the word was first used in English in a review of it), coined from Greek polys "many" (from PIE root *pele- (1) "to fill") + nēsos "island" (see Chersonese). Related: Polynesian.

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.

peninsula south of Thrace, from Greek khersonesos "peninsula," etymologically "island connected to the mainland," from khersos "dry land, mainland" + nēsos "island," also "(flooded) land near a river, alluvial land," which is of uncertain origin; traditionally from PIE root sna- "to swim," but this is now generally rejected. "As words for 'island' differ from language to language, [nēsos] is probably an Aegean loan (note that Lat. insula is also of unclear origin)" [Beekes]. Compare isle.

 Greek khersos is perhaps from PIE root *ghers- "to bristle" (see horror (n.)) if the Greek word first referred to "arid, stubbly land, and only later to land in opposition to water" [Beekes].