Isiac is a distinctive boys' name in United States, ranking #8576 in 1997 with 6 recorded births. This places Isiac in the bottom 21% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2001 with 15 births ranking #4979. In 1997, approximately 1 in every 314,182 boys born was named Isiac. STABLE Recent data shows the name is currently stable.