crotchet

Concise Oxford English Dictionary © 2008 Oxford University Press:
crotchet /ˈkrɒtʃɪt/

▶noun

• 1 Music, Brit. a musical note having the time value of a quarter of a semibreve or half a minim, represented by a large solid dot with a plain stem.

• 2 a perverse or unfounded belief or notion.

– origin ME (in the sense ‘hook’): from OFr. crochet, dimin. of croc, from ON krókr.