The term for the smallest meaningful unit of sound in a language is

The correct answer is phoneme.

Let's break down the linguistic terms to understand why:
1. Phoneme: This is the smallest distinct unit of sound in a language that can distinguish one word from another. For example, the words "pat" and "bat" differ by only one phoneme (the sound of /p/ versus /b/). Since phonemes are units of sound, they do not carry meaning on their own, but they are the smallest meaningful units of sound.
2. Morpheme: This is the smallest grammatical unit of meaning in a language. A morpheme can be a word (like "cat") or a word element (like the prefix "un-" or the suffix "-s").
3. Syntax: This refers to the rules that govern the structure and arrangement of sentences, including word order.
4. Semantics: This is the study of meaning in language, focusing on the relationship between signifiers (like words, phrases, and symbols) and what they stand for.

Therefore, the term for the smallest meaningful unit of sound is a phoneme.