O.E. feower, from P.Gmc. *petwor- (cf. O.S. fiwar, O.Fris. fiuwer, Frank. fitter-, Du. and Ger. vier, O.N. fjorir, Dan. fire, Sw. fyra), from PIE *qwetwor (cf. Skt. catvarah, Avestan čathwaro, Pers. čatvar, Gk. tessares, L. quattuor, Oscan petora, O.C.S. četyre, Lith. keturi, O.Ir. cethir, Welsh petguar). The phonetic evolution of the Germanic forms has not been fully explained. Slang four-eyes "person who wears glasses" first recorded 1874. Four-flusher is 1904, from verb four-flush "to bluff a poker hand, claim a flush with only four cards in the suit" (1896). Four-letter word first attested 1934; four-letter man, however, is recorded from 1923 (as a euphemism for a shit). A four-in-hand (1793) was a carriage with four horses driven by one person; in the sense of "loosely tied necktie" it is attested from 1892. To study The History of the Four Kings (1760, cf. Fr. Livres des Quatre Rois) contains euphemistic slang phrase for "a pack of cards" from the time when card-playing was considered a wicked pastime for students. Slang 4-1-1 is from the telephone number called to get customer information.