(bound form) the thorax or chest cavity, specifically the area between the chest and back containing the heart and lungs; often appears in 胸膛 xiōng​táng

(bound form) an inside cavity or hollow part of an object, such as the chamber of a gun or the firebox of a stove; often appears in 枪膛 qiāng​táng or 炉膛 lú​táng