I picked up my daughter from daycare and found a note in her cubby asking us to cut her carrots into smaller pieces if we were going to send them as a snack. Coincidentally, the note was written on the back of a tear-off word-of-the-day calendar, and the word for that day was snack.
A snack as a morsel of food (or to eat such a morsel), it turns out, is only one of the many meanings for the word. Its more common meaning was the snap or bite of a dog (possibly a form of onomatopoeia). This lead to the meaning as we know it (imagine a dog chomping away on a found morsel). It could also be used as a snarky comment, from the same derivation.
Amazingly, there were several other definitions in the O.E.D. A snack is also a type of ship as well as a dried fungus that could be used as kindling. It can also be used as an adverb or adjective: “There is no need to be snack and nasty about it” or “She answered me chastly an snack.”
I can never look at the word the same way again.