英语词源字典 - 在线词源网站

AIDS (n.)[AIDS 词源字典]: 1982, acronym formed from acquired immune deficiency syndrome. AIDS cocktail attested by 1997, the thing itself said to have been in use from 1995.[AIDS etymology, AIDS origin, 英语词源]
amidst (prep.): a variant of amid (q.v.) with adverbial genitive -s and parasitic -t. Amidde became amyddes (13c.) and acquired a -t by 1560s, probably by association with superlatives in -st.
There is a tendency to use amidst more distributively than amid, e.g. of things scattered about, or a thing moving, in the midst of others. [OED]
braids (n.): 1520s; see braid (n.).
didst: archaic 2nd person singular past indicative of do (q.v.).
hemorrhoids (n.): plural of hemorrhoid; late 14c., emeroudis, from Old French emorroides (13c.), from Latin hæmorrhoidae, from Greek haimorrhoides (phlebes) "(veins) liable to discharge blood," plural of haimorrhois, from haima "blood" (see -emia) + rhoos "a stream, a flowing," from rhein "to flow" (see rheum). Related: Hemmorhoidal.
maidservant (n.): 1520s, from maid (n.) + servant.
midshipman (n.): c. 1600, originally so called because he was stationed amidships when on duty (see amid).
midst (n.): c. 1400, from Middle English middes (mid-14c.), from mid + adverbial genitive -s. The parasitic -t is perhaps on model of superlatives (compare against).
midstream (n.): also mid-stream, Old English midstream; see mid + stream (n.).
midsummer (n.): Old English midsumor, from mid + sumor "summer" (see summer (n.1)). Midsummer Day, as an English quarter-day, was June 24. Astronomically June 21, but traditionally reckoned in Europe on the night of June 23-24.
rapids (n.): 1765, from French rapides (see rapid); applied by French voyagers to rough, swift-flowing reaches in North American rivers.
SIDS (n.): 1970, acronym for Sudden Infant Death Syndrome.
adenoids: "A mass of enlarged lymphatic tissue between the back of the nose and the throat, often hindering speaking and breathing in young children", Late 19th century: adenoid from Greek adēn 'gland' + -oid.