הילל
hêylêl
hay-lale'
From H1984 (in the sense of brightness); the morning star
KJV Usage: lucifer.

Brown-Driver-Briggs' Hebrew Definitions

הילל
Lucifer = "light-bearer"
1. shining one, morning star, Lucifer
a. of the king of Babylon and Satan (fig.)
2. (TWOT) 'Helel' describing the king of Babylon
Origin: from H1984 (in the sense of brightness)
TWOT: 499a
Parts of Speech: Noun Masculine