Ornithology 【鸟】
- (of a bird) having a flat breastbone without a keel, and so unable to fly（鸟）平胸的; 有平胸的。与CARINATE 相对。
- any of the mostly large, flightless birds with such a breastbone, i.e. the ostrich, rhea, emu, cassowary, and kiwi, together with the extinct moa and elephant bird平胸鸟。
词源
late 19th cent.: from Latin ratis 'raft' + -ITE1.