Trigraph may refer to:
Trigraph (orthography), a combination of written letters used to represent a sound
Computing Digraphs and trigraphs (programming), a group of characters used to symbolise one character An octal or decimal representation of byte values Mnemonics for machine language instructions As language codes in ISO 639
Cryptography As substitution group in a substitution cipher As combinations in the Ling Qi Jing
Mathematics As a generalization of graphs where there is a set of edges called semi-adjacent
See also Digraph (disambiguation) Tetragraph Multigraph (disambiguation)