Nope, it's definitely Mr., which possibly explains why "Master" practically disappeared. And while it may have been used to address boys, it could be comparabl

Nope, it's definitely Mr., which possibly explains why "Master" practically disappeared. And while it may have been used to address boys, it could be comparable to Mme and Mlle in French. An older but still unmarried woman would be addressed as madame, but the marriage distinction still exists otherwise. "Master Bruce (Wayne)" was definitely not a boy, as an example in (something like) literature.