schoolma'am
Webster's Dictionary (GCIDE)
Schoolma'am \School"ma'am\, n. A schoolmistress. [Colloq.U.S.] [1913 Webster]
WordNet 3.0
schoolma'am n 1: a woman schoolteacher (especially one regarded as strict) [syn: schoolmarm, schoolma'am, schoolmistress, mistress]