Grapheme refers to the smallest unit of a writing system that can carry meaning. Synonyms for grapheme could include character, letter, symbol, mark, sign, or glyph. Each of these terms can generally be used interchangeably with grapheme to describe the smallest visible or audible unit of a language system. While grapheme typically refers to written units, sign and mark may also be used for non-written systems such as sign language or musical notation. Overall, synonyms for grapheme can provide alternative ways to describe the building blocks of written or spoken language systems, allowing for more nuanced discussion of linguistic features.