Why is a crotchet called quarter note.?

A crotchet, commonly known as a quarter note in American music terminology, is called so because it represents one quarter of a whole note (or semibreve). In a 4/4 time signature, there are four beats in a measure, and each crotchet accounts for one beat, hence the name "quarter." This terminology helps musicians understand the note's duration and its relationship to the whole note.