an·trum /ˈæntrəm/ 竇,腔,房
an·trum /ˈæntrəm/ 名詞 竇,房
An·trum n.; pl. Antra A cavern or cavity, esp. an anatomical cavity or sinus. ◄ ►
antrum n : a natural cavity or hollow in a bone [also: antra (pl)]