crotchet
Definitions
A musical note having the time value of a quarter of a semibreve or a half of a minim; a quarter note.
A perverse or whimsical idea; a peculiar fancy or stubborn notion.
A small hook or hooked instrument.
Examples
The music teacher instructed the student to hold the crotchet for exactly one beat.
She had a strange crotchet about never walking under ladders, regardless of how much time it added to her commute.