Which term defines a sequence of letters representing a phonological unit in different words?

The term that defines a sequence of letters representing a phonological unit in different words is a phonogram. A phonogram typically includes groups of letters that correspond to a specific sound or sounds, which can be found across various words. For example, the “-at” in hat, cat, and sat all represent the same phonological unit and share a similar sound pattern, making “-at” a phonogram.

Phonemes refer to the smallest units of sound in a language, syllables are units of pronunciation that typically include a vowel sound and may have consonants, and morphemes are the smallest meaningful units of language that can stand alone or be part of a word. While these terms are important in understanding language structure, they do not specifically describe a sequence of letters that represents a sound across different words like phonograms do.