柯林斯詞典bursa /?b??s?/ 1. N a small fluid-filled sac that reduces friction between movable parts of the body, esp at joints (尤指關(guān)節(jié)処的)滑囊 返回 bursa劍橋詞典a sac (= part of the body like a bag ) that is filled with fluid and protects tissue from injury due to friction 囊 返回 bursa