Source : Webster's Revised Unabridged Dictionary (1913)

Bursa \Bur"sa\, n.; pl. {Burs[ae]}. [L. See {Burse}.] (Anat.)
   Any sac or saclike cavity; especially, one of the synovial
   sacs, or small spaces, often lined with synovial membrane,
   interposed between tendons and bony prominences.

Source : WordNet®

bursae
     See {bursa}