1 N-COUNT 洞;孔;腔 A cavity is a space or hole in something such as a solid object or a person's body. 洞;孔;腔 [formal]

2 N-COUNT (牙科)龋洞，蛀牙洞 In dentistry, a cavity is a hole in a tooth, caused by decay. (牙科)龋洞，蛀牙洞 [technical]