digraph

noun4

1. •
   A two-character sequence used to enter a single conceptual character.
2. •
   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. — 2022
3. •
   A directed graph.
4. •
   a sequence of two lines, each of which may be unbroken, broken once, or broken twice.