The Proto-Semitic word ṯ̣il(l)
Word ṯ̣il(l)
Meaning shadow

Comments
Kaye, Alan S. "Christopher Ehret. Reconstructing Proto-Afroasiatic (Proto-Afrasian): Vowels, Tone, Consonants, and Vocabulary", University of California 1995

Other words that might be of interest
nwr ‘light, to shine’, θ̣lm ‘black, darkness’, nīr, nūr ‘light’, nVgVh ‘shine’, ġarb ‘sunset, evening’, ʾiš ‘fire’, śamš ‘sun’