SG Heritage Dictionary

Heliacal [Adjective] Webster's Dictionary 1828

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.

Heliacal [Adjective] Webster's Dictionary 1913

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.

Heliacally [Adverb] Webster's Dictionary 1828

A star rises heliacally when it emerges from the sun's light, so as to be visible. [See the preceding word.]

Heliacally [Adverb] Webster's Dictionary 1913

In a heliacal manner.