fiveyoudaoicibaDictYouDict[five 词源字典]
five: [OE] Five is one of a general Indo-European family of words signifying ‘five’. It goes back ultimately to Indo-European *pengke, which also produced Greek pénte (source of English pentagon [16], pentecost [OE] – literally ‘fiftieth day’ – pentagram [19], etc), Sanskrit panca (source of English punch ‘spiced drink’), and Latin quīnque. In due course this under-went a phonetic transformation to *pempe, which was the direct ancestor of prehistoric Germanic *fimfi. This led on in its turn to German fünf, Dutch vijf. Swedish and Danish fem, and English five.
=> finger, fist, pentagon, punch[five etymology, five origin, 英语词源]
five (n.)youdaoicibaDictYouDict
Old English fif "five," from Proto-Germanic *fimfe (cognates: Old Frisian fif, Old Saxon fif, Dutch vijf, Old Norse fimm, Old High German funf, Gothic fimf), from PIE *penkwe- (cognates: Sanskrit panca, Greek pente, Latin quinque, Old Church Slavonic peti, Lithuanian penke, Old Welsh pimp). The sound shift that removed the *-m- is a regular development involving Old English, Old Frisian, and Old Saxon (as in thought, from stem of think; couth from *kunthaz; us from *uns).

Five-and-ten (Cent Store) is from 1880, American English, with reference to prices of goods for sale. Five-star (adj.) is from 1913 of hotels, 1945 of generals. Slang five-finger discount "theft" is from 1966. The original five-year plan was 1928 in the U.S.S.R. Five o'clock shadow attested by 1937.
[under picture of a pretty girl] "If I were a man I'd pay attention to that phrase '5 O'Clock Shadow.' It's that messy beard growth which appears prematurely about 5 P.M." [Advertisement for Gem razors and blades, Life," May 9, 1938]
fivefold (adv.)youdaoicibaDictYouDict
1570s, from earlier use as an adjective, from Old English fiffeald (adj.); see five + -fold.
fiver (n.)youdaoicibaDictYouDict
1843, "five-pound note," from five + -er.
high-fiveyoudaoicibaDictYouDict
originally U.S. basketball slang, 1980 as a noun, 1981 as a verb, though the greeting itself seems to be older (Dick Shawn in "The Producers," 1968). In reference to the five fingers of the hand.
fivesyoudaoicibaDictYouDict
"A game, played especially in the UK, in which a ball is hit with a gloved hand or a bat against the walls of a court with three walls ( Eton fives) or four walls ( Rugby fives)", Mid 17th century: plural of five used as a singular noun; the significance is unknown.