Source : Webster's Revised Unabridged Dictionary (1913)

Antelucan \An`te*lu"can\, a. [L. antelucanus; ante + lux light.]
   Held or being before light; -- a word applied to assemblies
   of Christians, in ancient times of persecution, held before
   light in the morning. ``Antelucan worship.'' --De Quincey.