layil, “night,” strong’s H3915

The first occurrence.

And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day. Gen 1:5

The primitive root.

Strong’s H3915 layil, a concrete noun meaning, “night;” from Strong’s H3883 luwl, a concrete noun meaning, “winding stair;” from an unused primitive root meaning, “to fold back.” The 3-letter root of the noun is lamed + vav + lamed.

lamed ל  = the shepherd’s staff, thus teach, yoke, to, bind
vav ו  = the tent peg, thus add, secure, hook
lamed ל  = the shepherd’s staff, thus teach, yoke, to, bind

The story: The staff (lamed) attached (vav) to the staff (lamed), i.e., a scroll, as the night sky unrolls as a scroll at the end of the day.

THE ANCIENT HEBREW LEXICON | INDEX OF HEBREW ROOTS