1) Abc or xyz 2) Any three-letter sequence 3) MNO on a telephone dial 4) Three-letter combo 5) Three-letter sequence 6) Written word 
Trigrams are a special case of the N-gram, where N is 3. They are often used in natural language processing for doing statistical analysis of texts. ==Frequency== The 16 most common character-level trigrams in English are: ==Examples== The sentence `the quick red fox jumps over the lazy brown dog` has the following word level trigrams: And the w.....
• (n.) Same as Trigraph.
[n] - a word that is written with three letters in an alphabetic writing system
trigram An inscription of three letters.
noun a word that is written with three letters in an alphabetic writing system