digraphs

/D IH0 G R AE0 F S/
noun
  1. 1

    A directed graph.

noun
  1. 1

    A two-character sequence used to enter a single conceptual character.

  2. 2

    A pair of letters, especially a pair representing a single phoneme.

Source: https://en.wiktionary.org/wiki/digraph, https://en.wiktionary.org/wiki/digraphs