Added 9 October 2026 isaac noun Categories: PeopleUncommon Words noun ! Definition from WordNet 3.1, Princeton University. More about isaac at Wordnik → Where our words come from → (Old Testament) the second patriarch; son of Abraham and Sarah who was offered by Abraham as a sacrifice to God; father of Jacob and Esau. Related Words: isaiahyitzhakitzhakissacishaqcohnishakisaakisakyitzchokisackisaka Back to today's word