Isac is the Romanian form of Isaac, as well as a Swedish variant form (alongside Isak). The name traces its roots to the Hebrew Yitsḥaq, derived from the root tsaḥaq meaning "to laugh" or "to rejoice." In the Old Testament, this etymology is explained by the laughter of Abraham and Sarah upon hearing that they would have a son in their old age (see Genesis 17:17 and Genesis 18:12). Isaac, the biblical patriarch, married Rebecca and fathered Esau and Jacob. Etymology and Cultural Forms The name Isaac has given rise to numerous forms across languages. In Romanian, the adaptation is Isac, while in Swedish it alternates with Isak (Swedish official spelling). Other languages also have their own variants: Ishaq in Arabic, Yitzchaq in Biblical Hebrew, Isaak in Russian, and Sahak in Armenian, among many others. This wide distribution reflects the name's significance in Judaism, Christianity, and Islam. Notable Bearers and Historical Context As an English Christian name, Isaac was used occasionally during the Middle Ages but was far more common among Jews. Its popularity grew significantly after the Protestant Reformation, and it spread through English-speaking countries to many parts of the world. Renowned figures include physicist Isaac Newton and writer Isaac Asimov. Though Isac is less widespread globally, it remains a recognized masculine name in Romania and Sweden. According to Wiktionary, it entered Swedish as a less common spelling of Isak, carrying the same biblical heritage and joyful meaning. Meaning: He will laugh, he will rejoice Origin: Hebrew, via Romanian and Swedish Type: Given name Usage Regions: Romania, Sweden