hemi-youdaoicibaDictYouDict[hemi- 词源字典]
word-forming element meaning "half," from Greek hemi- "half," from PIE root *semi-, which is the source of Sanskrit sami, Latin semi- (see semi-), Old High German sami- "half," and Old English sam-, denoting a partial or imperfect condition (see sandblind).[hemi- etymology, hemi- origin, 英语词源]
sand-blind (adj.)youdaoicibaDictYouDict
also sandblind, "half-blind," c. 1400, probably altered (by influence of sand) from Old English *samblind, the first element from West Germanic *sami-, from PIE *semi- (see semi-); compare Old English samlæred "half-taught, badly instructed," samstorfen "half-dead."
semi-youdaoicibaDictYouDict
before vowels sem-, word-forming element meaning "half, part, partly; partial, imperfect; twice," from Latin semi- "half," from PIE *semi- "half" (cognates: Sanskrit sami "half," Greek hemi- "half," Old English sam-, Gothic sami- "half").

Old English cognate sam- was used in such compounds as samhal "poor health," literally "half-whole;" samsoden "half-cooked," figuratively "stupid" (compare half-baked); samcucu "half-dead," literally "half-alive;" and the last survivor of the group, sandblind "dim-sighted" (q.v.). Common in Latin (as in semi-gravis "half-drunk," semi-hora "half hour," semi-mortuus "half-dead," semi-nudus "half-naked," semi-vir "half-man, hermaphrodite"). The Latin-derived form in English has been active in forming native words since 15c.