The term "phonetic unit" refers to a sound or a group of sounds that make up a word. There are several synonyms for this term, including phoneme, speech sound, and sound segment. A phoneme is the smallest unit of sound in a language and can change the meaning of a word when substituted. A speech sound refers to any sound that can be produced by a human voice, including vowels, consonants, and diphthongs. A sound segment is a group of speech sounds that are linked together to form a word. These synonyms help linguists and language learners understand the intricacies of phonetics and pronunciation in different languages.