Trigraph

• POS: Noun
• HYPHEN: tri=graph

CIDE DICTIONARY

Trigraph, n. [Pref. tri- + -graph.].

 Three letters united in pronunciation so as to have but one sound, or to form but one syllable, as -ieu in adieu; a triphthong.  [1913 Webster]

OXFORD DICTIONARY

Trigraph, n. (also trigram)
1 a group of three letters representing one sound.
2 a figure of three lines.

ROGET THESAURUS

Trigraph

Letter

N letter, character, hieroglyphic, type, capitals, digraph, trigraph, ideogram, ideograph, majuscule, minuscule, majuscule, minuscule, alphabet, ABC, abecedary, christcross-row, consonant, vowel, diphthong, triphthong, mute, liquid, labial, dental, guttural, syllable, monosyllable, dissyllable, polysyllable, affix, suffix, spelling, orthograph, phonography, phonetic spelling, anagrammatism, metagrammatism, cipher, monogram, anagram, doubleacrostic, literal, alphabetical, abecedarian, syllabic, majuscular, minuscular, uncial.