Definitions for "Digraph"
Keywords:  consonant, bread, sing, vowel, letter
Two signs or characters combined to express a single articulated sound; as ea in head, or th in bath.
two adjacent letters representing on speech sound. It can be two consonants (th, sh, ng) or two vowels (ea, ay, ei).
Two letters together that make one sound. For example, the two letters sh in the word fish make one sound.
A digraph (or a directed graph) is a graph in which the edges are directed. (Formally: a digraph is a (usually finite) set of vertices V and set of ordered pairs ( a,b) (where a, b are in V) called edges. The vertex is the initial vertex of the edge and the terminal vertex.
a pair of signs or symbols (two graphs), which together represent a single sound or a single linguistic unit. The English writing system employs many digraphs (for example, th, ch, sh, qu, and so on). The same two symbols may not always be interpreted as a digraph (for example, ca th ode versus ca th ouse).
A geometric diagram consisting of a finite number of dots called vertices joined by a finite number of curved or straight line segments with an arrow on each called directed edges.
Keywords:  union