Master
A master, in Hermetic society, is the owner (and teacher) of an apprentice. Master is the generic term, but an apprentice to a maga would refer to her as his mistress. It is an honorific title, and once an apprentice has concluded his gauntlet he is expected to refer to his "parens" (or "pater or "mater") instead. Some magi may retain the old manner of speech out of habit.