Casimir is a distinctive boys' name in United States, ranking #3543 in 2018 with 31 recorded births. The name reached its all-time peak in 2025 with 73 births ranking #2039. Since 1996, the popularity has increased by 210.0%. In 2018, approximately 1 in every 58,564 boys born was named Casimir. RISING Recent data shows the name is currently rising.