digraph

noun

1. A directed graph.
2. A two-character sequence used to enter a single conceptual character.
3. A pair of letters, especially a pair representing a single phoneme.

   “As a special education teacher, I find that introducing one or two digraphs a week works well.”

   “A consonant digraph is a combination of two consonants that represent one sound.”

4. a sequence of two lines, each of which may be unbroken, broken once, or broken twice.