Final answer:
A digraph is a letter combination where one or more letters are silent but another letter represents the phoneme.
Step-by-step explanation:
A letter combination where one or more letters are silent but another letter represents the phoneme is called a digraph.
A digraph is a combination of two letters used to spell a single sound. For example, the letter combination 'ea' in 'beach' represents the long 'e' sound. Digraphs can be found in words of Greek or Anglo-Saxon derivation, such as 'light' or 'phone'.