n. (also y) (pl. Ys or Y's)
1 the twenty-fifth letter of the alphabet.
2 (usu. y) Algebra the second unknown quantity.
3 Geom. the second coordinate.
4 a a Y-shaped thing, esp. an arrangement of lines, piping, roads, etc. b a forked clamp or support.
abbr. (also Y.)
3 US = YMCA, YWCA.
symb. Chem. the element yttrium.
Useful english dictionary. 2012.