If you took piano lessons as a child in the United States, “semiquaver” might be a new word for you. It’s the British musical notation version of a sixteenth note. Correspondingly, “quaver” is an eighth note, “crotchet” is a quarter note, “minim” is a half note, and “semibreve” is a whole note. “Semiquaver” is also used figuratively to refer to a very brief period of time, similar to the phrase “just a second.”