digraph

名词 digraph:

1. two successive letters (especially two letters used to represent a single sound: `sh' in `shoe')
   同义词：digram

di.graph

n.（名词）
A pair of letters representing a single speech sound, such as theph in pheasant or the ea in beat.
二合字母：一对字母发一个音，例如pheasent 中的 ph 或 beat 中 ea
A single character consisting of two letters run together and representing a single sound, such as Old Englishô .
二合字母：两个字母连在一起成为复合字母，发一个音，例如老式英语ô

【引伸】
digraph.ic