Webster’s Revised Unabridged Dictionary · 1913
Genethliac
Ge·neth′li·ac (jē·nĕth′lĭ·ăk), a. [L. genethliacus, Gr. γενεθλιακός, fr. γενέθλιος belonging to one's birth, γενέθλη birth, fr. γίγνεσθαι to be born.] Pertaining to nativities; calculated by astrologers; showing position of stars at one's birth. Howell.
Ge·neth′li·ac, n. 1. A birthday poem.
2. One skilled in genethliacs.