It derives its form from the Latin Y, which is from the Greek Υ, originally the same letter as V. Etymologically, it is most nearly related to u, i, o, and j. g; as in full, fill, AS. fyllan; E. crypt, grotto; young, juvenile; day, AS. dæg. See U, I, and J, G. [ 1913 Webster ]

☞ Y has been called the Pythagorean letter, because the Greek letter Υ was taken to represent the sacred triad, formed by the duad proceeding from the monad; and also because it represents the dividing of the paths of vice and virtue in the development of human life. [ 1913 Webster ]

Y level (Surv.), an instrument for measuring differences of level by means of a telescope resting in Y's. --
Y moth (Zool.), a handsome European noctuid moth Plusia gamma) which has a bright, silvery mark, shaped like the letter Y, on each of the fore wings. Its larva, which is green with five dorsal white species, feeds on the cabbage, turnip, bean, etc. Called also gamma moth, and silver Y. [ 1913 Webster ]

That no wight mighte it see neither yheere. Chaucer. [ 1913 Webster ]

Neither to ben yburied nor ybrent. Chaucer. [ 1913 Webster ]

☞ Some examples of Chaucer's use of this prefix are; ibe, ibeen, icaught, ycome, ydo, idoon, ygo, iproved, ywrought. It inough, enough, it is combined with an adjective. Other examples are in the Vocabulary. [ 1913 Webster ] Spenser and later writers frequently employed this prefix when affecting an archaic style, and sometimes used it incorrectly. [ 1913 Webster ]

☞ The name is also applied to allied species. [ 1913 Webster ]

Yacht measurement. See the Note under Tonnage, 4. [ 1913 Webster ]