bur·sa
noun/ˈbɜːsə/
/ˈbɜːrsə/
(plural bursae
(anatomy)/ˈbɜːsiː/
/ˈbɜːrsiː/
, bursas)- a part inside the body like a bag, which is filled with liquid, especially around a joint so that it can work smoothly
囊；黏液囊 Word Originearly 19th cent.: from medieval Latin, ‘bag, purse’, from Greek bursa ‘leather’.