Lewis & Short

lūcesco and lūcisco, ĕre, v. inch. n. [luceo], to begin to shine.

  1. I. Lit.
    1. A. In gen.: sol lucescit, Verg. E. 6, 37: quorum caput flavo capillorum crine lucescat, Firm. Math. 4, 13.
    2. B. In partic., of the break of day, to grow light, break, dawn: nonae lucescunt, Ov. F. 5, 417.
      1. 2. Impers.: lucescit or luciscit, the day is breaking: eamus, Amphitruo: luciscit hoc jam, it is getting light there (in the sky), Plaut. Am. 1, 3, 45; Ter. Heaut. 3, 1, 1; v. luceo, I. A. fin.: cum lucisceret, as soon as it grew light, at break of day, *Cic. Fam. 15, 4, 8: et jam lucescebat, Liv. 4, 28.
  2. II. Trop.: luciscens amor, bright, Front. ad Anton. 1, 5 Mai.