[ hi-lahy-uh-kuh l ]
/ hɪˈlaɪ ə kəl /

adjective Astronomy.

pertaining to or occurring near the sun, especially applied to such risings and settings of a star as are most nearly coincident with those of the sun while yet visible.


Also he·li·ac [hee-lee-ak] /ˈhi liˌæk/.

Origin of heliacal

1600–10; < Late Latin hēliac(us) (< Greek hēliakós; see heli-1, -ac) + -al1
Related formshe·li·a·cal·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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