Which term describes standalone words like "big," "book," and "walk"?

The term that describes standalone words like "big," "book," and "walk" is a free morpheme. Free morphemes are the smallest units of meaning that can stand alone as words without needing to be attached to other morphemes. They convey specific meanings and can function independently in sentences, making them essential components of language. This distinguishes them from bound morphemes, which cannot stand alone and must be attached to other morphemes to convey meaning, such as prefixes or suffixes.

Understanding that "big," "book," and "walk" can exist on their own and represent full concepts is crucial in phonetics and morphology, as it reflects how words are constructed and how they function syntactically. The other terms, such as allomorphs (which are variants of a morpheme that appear in different contexts) and morpheme (a general term for any meaningful unit), do not specifically denote standalone words and are therefore less precise in this context.