ab, “father,” strong’s H1

First occurrence

Therefore shall a man leave his father and his mother, and shall cleave unto his wife, and they shall be one flesh. Gen 2:24

The primitive root

Strong’s H1 אב ab, a primitive noun (with no verbal root) meaning, “father.” The pictographs are aleph + bet. 

aleph א = the ox head, thus strength, power, leader
bet ב = the house, thus house, household, family, in, within

The story being told is that the father is the strong one (aleph) of the house (bet).

THE ANCIENT HEBREW LEXICON | INDEX OF HEBREW ROOTS