Casimir is a distinctive boys' name in United States, ranking #5074 in 1999 with 13 recorded births. The name reached its all-time peak in 2025 with 73 births ranking #2039. Since 1996, the popularity has increased by 30.0%. In 1999, approximately 1 in every 147,699 boys born was named Casimir. RISING Recent data shows the name is currently rising.