heliacal

Etymology

From Ancient Greek ἡλιακός (hēliakós, “of the sun”) + -al. Appears in English first in the 16th century.

adj

1. (rare) Of or relating to the Sun, especially rising and setting with the sun.
2. Of or relating to the rising of a star when it first becomes visible just before sunrise in the eastern sky, having previously been made invisible by sunlight, or the analogous situation of its setting just after sunset.