To concatenate means to string together different things. Concatenating "snow" and "ball" produces "snowball." But what would the opposite action be? What is the name of the action used to derive two words from one?
(My dictionaries don't list any antonyms, and Googling revealed how to do the opposite but not what it's called.)
Edit: I had programming parlance in mind, so I've reflected that in the question title.