Entry 1 sense Webster, 1913 Pepper box /pĕp'-ẽr bäks/ · Pep·per box · IPA 01 n. A buttress on the left-hand wall of a fives court as the game is played at Eton College, England. 1. A buttress on the left-hand wall of a fives court as the game is played at Eton College, England.