Casimir is a distinctive boys' name in United States, ranking #3307 in 2015 with 34 recorded births. The name reached its all-time peak in 2025 with 73 births ranking #2039. Since 1996, the popularity has increased by 240.0%. In 2015, approximately 1 in every 56,361 boys born was named Casimir. RISING Recent data shows the name is currently rising.