Combining form

A combining form is a lexical stem, usually of Latin or Greek origin, which is added to, usually, other combining forms to form a word. Typical initial combining forms include eco-; geo- and tele-; typical final combining forms include -logy; -nomy; -scope.

Combining forms may often be confused with prefixes or suffixes. The difference is that the latter two are added to existing words to create new words.