Entry 1 sense Webster, 1913 Pitchblende /pĭch'-blĕndˌ/ · Pitch·blende · IPA /ˈpɪtʃblɛnd/ 01 n. A pitch-black mineral consisting chiefly of the oxide of uranium; uraninite. See Uraninite. 1. A pitch-black mineral consisting chiefly of the oxide of uranium; uraninite. See Uraninite.(Min.) See: Uraninite