One of the mysteries of the English language finally explained.
1Humorous. "on all fives": on hands, knees (or feet), and another part of the body (later especially the buttocks).
2Cards. A variation of all fours in which the winner of a trick scores the face value of any trump cards it contains, as well as an additional five points if the trick contains the five of trumps.
3Dominoes. A game in which points are scored only when the sum of the spots at the two ends is five or a multiple thereof.
Late 18th century; earliest use found in The Monthly Review. From all + the plural of five, after all fours.
all fives/ˌɔːl ˈfʌɪvz/
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