school-marm noun & adjective. ['sku:lmɑ:m] colloq. (orig. US). Also school-ma'am, school-ma'm. M19.
[from SCHOOL noun¹ + MARM.]
A. noun.
1. A schoolmistress. M19.

2. A tree which has forked to form two trunks. N. Amer. slang. M20.
b. adjective. Like a school-mistress, prim and correct. M20.

■ school-marming noun the occupation of being a school-mistress E20.

■ school-marmish adjective like or suggestive of a school-mistress; prim and correct: L19.

■ school-marmishly adverb M20.

■ school-marmy adjective school-marmish M20.

[TahlilGaran] English Dictionary ▲