It's most commonly used to describe a technique in string instruments, where the strings are plucked with the fingers instead of being bowed.
Here's why the name makes sense:
* "Pizzicare" is the Italian verb for "to pluck."
* "Pizzicato" is the past participle of the verb, meaning "plucked."
So, when a musician instructs another to play "pizzicato", they are asking them to pluck the strings instead of bowing them.