Ŏpālĭa, ium, n.,
a festival celebrated on the 19 th of December , in honor of the goddess Ops , Varr. L. L. 6, § 22 Müll.; cf.: Opalia dies festi, quibus supplicatur Opi, Paul. ex Fest. p. 185 Müll.; Macr. S. 1, 10.