Isiac is a distinctive boys' name in United States, ranking #7429 in 1999 with 8 recorded births. This places Isiac in the bottom 36% 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 1999, approximately 1 in every 240,011 boys born was named Isiac. STABLE Recent data shows the name is currently stable.