Definify.com
Webster 1913 Edition
Heliacal
He-li′a-cal
,Adj.
[Gr. [GREEK] belonging to the sun, fr. [GREEK] the sun: cf. F.
héliaque
.] (Astron.)
Emerging from the light of the sun, or passing into it; rising or setting at the same, or nearly the same, time as the sun.
Sir T. Browne.
☞ The heliacal rising of a star is when, after being in conjunction with the sun, and invisible, it emerges from the light so as to be visible in the morning before sunrising. On the contrary, the heliacal setting of a star is when the sun approaches conjunction so near as to render the star invisible.
Webster 1828 Edition
Heliacal
HELI'ACAL
,Adj.
Emerging from the light of the sun, or passing into it. The heliacal rising of a star, is when, after being in conjunction with it and invisible, it emerges from the light so as to be visible in the morning before sunrising. On the contrary, the heliacal setting of a star, is when the sun approaches so near as to render it invisible by its superior splendor.