"a beau," 1620s, from Gk. Adonis, name of the youth beloved by Aphrodite, from Phoenician adon "lord," probably originally "ruler," from base a-d-n "to judge, rule." Adonai, an O.T. word for "God," is the Heb. cognate, with pl. of majesty.
Babylonian and Assyrian god (identified with Adon), probably from Babylonian Du'uzu, contraction of Dumu-zi "the son who rises," also interpeted as "the faithful son."
1535, from Heb. tammuz, tenth month of the Jewish civil year, fourth of the sacred, covering parts of June and July; also the name of a Syrian deity equivalent to Phoenician Adon, whose festival began with the new moon of this month (cf. Tammuz).