Crotchet \KROCH-it\ , noun;
1. An odd fancy or whimsical notion
2. A small hook
3. In British musical nomenclature, a quarter note
4. A curved surgical instrument with a sharp hook
This word dates to the late 14th century with the meaning "crocket," and later "small hook." It comes from Old French crochet, the diminutive of croc ("hook"). Croc comes from Old Norse krokr ("hook"), which is also the forebear of crook. The etymology before that is obscure, but it's possibly related to a big group of Germanic words that start with kr- and mean "bent, hooked".
I don't know about you, but my eyes were playing tricks on me with this one. At first I thought it was crochet, as in the yarn craft similar to knitting, so the 'whimsy' definition seemed very strange. Turns out, these two words are close relatives since crochet also comes from Old French crochet. Another related word is a favorite of mine, crotchety, which comes from the 'whimsy' definition and is first attested in 1825. It means "given to odd notions, whims, grouchiness, etc.".
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Wednesday, June 15
Etymologies come from the Oxford English Dictionary and/or Etymonline.com