Casimir is a distinctive boys' name in United States, ranking #4027 in 2007 with 25 recorded births. The name reached its all-time peak in 2025 with 73 births ranking #2039. Since 1996, the popularity has increased by 150.0%. In 2007, approximately 1 in every 83,009 boys born was named Casimir. RISING Recent data shows the name is currently rising.