quarter note
A note lasting one beat in common time, represented by a filled note head with a stem.
In Depth
The quarter note (called a crotchet in British terminology) is the most fundamental note value in common time (4/4). It receives one beat and serves as the standard unit when discussing tempo — a metronome marking of ♩= 120 means 120 quarter notes per minute.
Quarter notes are written as filled-in (solid black) oval note heads with a stem. When grouped in beams with eighth or sixteenth notes, the quarter note stands alone with its single stem. The quarter rest (a zigzag symbol) indicates one beat of silence. In compound time signatures like 6/8, the dotted quarter note (lasting 1.5 beats, equivalent to three eighth notes) becomes the primary beat unit.
The word crotchet (British for quarter note) comes from the French crochet, meaning a small hook — referring to the hook-shaped flag on the note's stem in early notation.