Digraph (orthography) facts for kids
A digraph, bigraph, or digram (from the Greek: δίς, dís, "double" and γράφω, gráphō, "write") is a one of the characters used to write one phoneme (distinct sound) or a sequence of phonemes that does not correspond to the normal numbers of the two characters in combination. The sound is usually in use, but not always, one of that can't be in expression using a only one character in the orthography used by the language.
Digraph (orthography) Facts for Kids. Kiddle Encyclopedia.