A grapheme (/græfi:m/) is the smallest unit of a writing system of any given language. An individual grapheme may or may not carry meaning by itself, and may or may not correspond to a single phoneme of the spoken language. Graphemes include alphabetic letters, typographic ligatures, numerical digits, punctuation marks, and other individual symbols.
The study of graphemes is graphemics.
Within language analysis, graphemes are often marked by round brackets, e.g (a) (b) (1) (2) (&), etc