Issac is a spelling variant of Isaac, which comes from the Hebrew Yitzchak and means "he will laugh", after Sarah's laughter when told she would bear a son in old age. The double s version has been in continuous use in America for generations, especially in Hispanic families, where it is pronounced like the Spanish Isaac. Issac ranked number 457 in 2000, peaked at number 376 in 2008 and has drifted down to number 915 in 2025.