Jahsiah is a modern American spelling of Josiah, the Hebrew Yoshiyahu, which means "Yahweh supports" or "Yahweh heals" and belonged to the reforming boy king of Judah. The Jah- opening spells out the divine name as in Jahmir and Jahmari, and the name is used mostly in African-American families. Jahsiah peaked at number 2,097 in 2019 and ranks number 2,694 among boys in 2025, with 48 births.