The term used to describe the beginnings of a word is "morpheme." A morpheme is the smallest grammatical unit in a language and can be a word or a part of a word, such as a prefix or suffix. Morphemes can be free, meaning they can stand alone as words (like "cat"), or bound, meaning they cannot stand alone and must attach to a free morpheme (like "un-" in "unknown"). This concept is essential in linguistics to understand how words are formed and meaning derived from them.