trigramPronunciation: /ˈtrʌɪgram/Definition of trigram noun 1another term for trigraph. 2 Linguistics a group of consecutive written units such as letters, syllables, or words. 3each of the eight figures formed of three parallel lines, each either whole or broken, combined to form the sixty-four hexagrams of the I Ching. trigram in other Oxford dictionaries Definition of trigram in the US English dictionary