A digraph is a term used in phonics to describe two consecutive letters that work together to make one sound. Digraphs can be made up of vowels or consonants, and they are a building block of literacy for any young reader. Consonant digraphs are a combination of two consonants that represent one sound, such as "ch" in "chin" or "sh" in "ship". Vowel digraphs are groups of two letters, at least one of which is a vowel, that make a single sound, such as "ow" in "slow".

Digraphs are often taught in order, starting with those most commonly appearing in English words. Teachers tend to look at one sound and then show children the various ways this can be made and written down as a grapheme (a combination of letters). For example, "true," "food," and "crew" all have the same /oo/ sound, represented by a different digraph each time.

It is important to note that a digraph is not a digraph when it crosses a syllable boundary. Children are taught about digraphs in phonics lessons in the Reception Year and Year 1 (aged 4, 5, and 6) in schools in England.