Xm., Xmas. Christmas.
Xn., Xtian. Christian.
y., yr. Year.
y., yd. Yard.
Ye. The (the Y not being a Y, but as representing the Anglo-Saxon þ).
Y.M.C.A. Young Men's Christian Association.
yr. Your; Younger.
Yt. That (Y as in Ye).
Y.W.C.A. Young Women's Christian Association.
Zn. Zinc.