ma·zel tov also ma·zal tov (mä'zəl tôf', tôv', tōv') interj. Used to express congratulations or best wishes.
[Mishnaic Hebrew mazzāl ṭôb, good luck : mazzāl, constellation, destiny (ultimately from Akkadian manzaltu, mazzaztum, position of a star, from izuzzu, to stand; see ḏwḏ1 in Semitic roots) + ṭôb, good; see ṭyb in Semitic roots.]