combining form
noun
°A form of a word used for combining with other words or other combining forms to make new words. A combining form may conjoin with an independent word (e.g., mini- + skirt), another combining form (e.g., photo- + -graphy) or an affix (e.g., cephal + -ic).
°In computer typography, the form of an accent that can be combined with other characters, as opposed to a single character that includes the accent.