Is boy a digraph

No, "boy" is not a digraph. A digraph consists of two letters that together represent a single sound, such as "ch" in "chop" or "sh" in "ship." In "boy," the "oy" does function as a single vowel sound, but it is not a traditional digraph in the same sense as those formed by two consonants. Instead, "oy" is classified as a vowel team.