Why is a group of fish called a school?

The word "school" for fish comes from Middle Dutch "schole" meaning "group or troop," unrelated to educational schools (from Greek "skholē" meaning leisure). The term describes fish swimming together in coordinated groups for protection, efficient feeding, and reproduction. The collective behavior resembles organized movement, hence "school." Other terms include "shoal" (more general grouping) and "school" (synchronized swimming). The terminology reflects the fish's collective, organized behavior rather than any connection to learning.