From Old Irish scol (compare Scottish Gaelic sgoil), from Latin schola, from Ancient Greek σχολή (skholḗ). The sense “school of fish” is either a borrowing from Middle English scole, schole (in the relevant sense), from Middle Dutch scole (“swarm of animals”), from Proto-Germanic *skulō (“crowd”); or a semantic loan from English school under the mistaken assumption that the “group of fish” sense is etymologically identical to the “educational institution” sense.