Origins of Mathematical Words: A Comprehensive Dictionary of Latin, Greek, and Arabic Roots

Y

344 W word This noun is cognate with the Latin verbum, which has the same meaning. Verbum, in turn, is related to the Greek e‡rw, which means to say, speak, or tell. X x-axis The use of the letters x, y, and z for unknown quantities is due to Descartes, who used the letters a, b, and c for known quantities. The Oxford English Dictionary says that there is no evidence to support the hypothesis that x is actually the metamorphosis of the medieval cursive r, the first letter and abbreviation of the noun res, thing. (Medieval authors writing in Latin referred to an unknown quality as res, that is, the thing. To abbreviate this reference, they used r, the first letter of that word.) Y y-axis The letter y is neither Latin nor Greek. Dr. Johnson says in his dictionary that it was a symbol much used by the Saxons instead of i. When transliterating Greek into English, y is to be used for upsilon. ...