What are the smallest units of meaning in a word called?

The smallest units of meaning within a word are known as morphemes. Morphemes can be whole words or parts of words, such as prefixes and suffixes. They are the building blocks of language, enabling us to convey specific meanings and grammatical functions.

For instance, the word "unhappiness" comprises three morphemes: "un-" (a prefix meaning "not"), "happy" (a root word), and "-ness" (a suffix that turns an adjective into a noun). This word exemplifies how morphemes combine to create a comprehensive meaning.

In contrast, prefixes are a type of morpheme but do not encompass all units of meaning. Syllables are units of sound within words and do not necessarily convey meaning on their own. Compound words consist of two or more whole words combined together, which makes them larger units than morphemes. Therefore, focusing on the concept of morphemes provides clarity on the fundamental components of meaning in linguistic structure.