Obs. rare. [perh. a. OF. *bosteor, var. of bouteor, f. bouter (also boster) to strike, knock, as in ‘bosterent a la porte’ (Godef.).]
perh. = Striker, knocker (a battering-ram).
c. 1425. Wyntoun, Cron., VIII. xxxiv. 23. Browcht a Gyne, men callyd Bowstowre For til assayle that stalwart towre.
