tideyoudaoicibaDictYouDict[tide 词源字典]
tide: [OE] Tide originally meant ‘time’ – as in the tautologous ‘time and tide wait for no man’. Like the related German zeit, Dutch tijd, and Swedish and Danish tid, all of which mean ‘time’, it comes from a prehistoric Germanic *tīdiz. This was derived from the base *tī- (source also of English time), which in turn went back to the Indo-European base *dī- ‘divide, cut up’ – so etymologically the word denotes ‘time cut up, portion of time’.

This notion of a ‘period’ or ‘season’ is preserved in now rather archaic expression such as Christmastide, Whitsuntide, and noontide. The application to the rise and fall of the sea, which emerged in the 14th century, is due to the influence of the related Middle Low German tīde and Middle Dutch ghetīde, where it presumably arose from the notion of the ‘fixed time’ of the high and low points of the tide. Betide [13] was formed from the now archaic verb tide ‘happen’, a derivative of the noun.
=> betide, tidy, time[tide etymology, tide origin, 英语词源]
tide (n.)youdaoicibaDictYouDict
Old English tid "point or portion of time, due time, period, season; feast-day, canonical hour," from Proto-Germanic *tidiz "division of time" (cognates: Old Saxon tid, Dutch tijd, Old High German zit, German Zeit "time"), from PIE *di-ti- "division, division of time," suffixed form of root *da- "to divide, cut up" (cognates: Sanskrit dati "cuts, divides;" Greek demos "people, land," perhaps literally "division of society," daiesthai "to divide;" Old Irish dam "troop, company").

Meaning "rise and fall of the sea" (mid-14c.) probably is via notion of "fixed time," specifically "time of high water;" either a native evolution or from Middle Low German getide (compare Middle Dutch tijd, Dutch tij, German Gezeiten "flood tide, tide of the sea"). Old English seems to have had no specific word for this, using flod and ebba to refer to the rise and fall. Old English heahtid "high tide" meant "festival, high day."
tide (v.)youdaoicibaDictYouDict
"to carry (as the tide does)," 1620s, from tide (n.). Usually with over. Earlier it meant "to happen" (Old English; see tidings). Related: Tided; tiding.