(US, slang) A woman who is a teacher, especially a teacher in a schoolhouse; may carry the connotation she is severe.The schoolmarm, running the old west one-room school, is a stock character in western movies.
A person, male or female, who exhibits characteristics attributed to schoolteachers of the old times (as strict adherence to arbitrary rules, is strict on those who don't comply to those rules, etc.)
(forestry) A tree with two or more trunks; a forked tree.