Answer:
Morpheme
Explanation:
Morpheme is the general term that is used in descriptive linguistics, for these units of meaning. A morpheme can be defined as the smallest unit with meaningful idea. Unlike a word, which can stand by its own, a morpheme may or may stand alone depending upon type of morpheme. They are classified into two types;
1. Free Morpheme - they can function independently
2. Bound Morpheme - they are dependent on other words, root, or other bound morphemes and also includes prefixes and suffixes.
For example:
un-trace-able is made up of three morphemes;
un - a bound morpheme meaning 'not'
trace - root, a free morpheme (can function independently)
able - free morpheme meaning 'to do something'
Morphemes are also categorized as either content morphemes or function morphemes.
Function morphemes => prepositions, pronouns, determiners, conjunctions etc.
Content morphemes => nouns, adverbs, adjectives, verbs etc