dealyoudaoicibaDictYouDict[deal 词源字典]
deal: English has two words deal. The one which now means chiefly ‘distribute’ goes back to Old English dǣl ‘part’ and its verbal derivative dǣlan ‘divide’. The noun (together with its relatives German teil, Dutch deel, and Gothic dails) goes back to a prehistoric Germanic *dailiz, a derivative of the base *dail-, which also produced English dole and ordeal. The ultimate source of this base is not known. Deal ‘(plank of) pine’ [14] was borrowed from Middle Dutch or Middle Low German dele.
=> dole, ordeal[deal etymology, deal origin, 英语词源]
deal (n.1)youdaoicibaDictYouDict
from Old English dæl "part, share, quantity, amount," from Proto-Germanic *dailaz (cognates: Old Norse deild, Old Frisian del, Dutch deel, Old High German and German teil, Gothic dails "part, share"), from PIE *dail- "to divide" (cognates: Old Church Slavonic delu "part," Lithuanian dalis).

Business sense of "transaction, bargain" is 1837, originally slang. Meaning "an amount" is from 1560s. New Deal is from F.D. Roosevelt speech of July 1932. Big deal is 1928; ironic use first recorded 1951 in "Catcher in the Rye." Deal breaker is attested by 1975.
deal (n.2)youdaoicibaDictYouDict
"plank or board of pine," c. 1400, from Low German (compare Middle Low German dele), from Proto-Germanic *theljon, from PIE root *tel- "ground, floor." An Old English derivative was þelu "hewn wood, board, flooring."
deal (v.)youdaoicibaDictYouDict
Old English dælan "to divide, distribute, separate, share, bestow, dispense," from the source of deal (n.). Meaning "to distribute cards before a game" is from 1520s. To deal with "handle" is attested from mid-15c. Related: Dealt; dealing.