The Collaborative International Dictionary of English v.0.48:
Synovial \Syn*o"vi*al\, a. [Cf. F. synovial.] (Anat.)
Of or pertaining to synovia; secreting synovia.
Synovial capsule, a closed sac of synovial membrane
situated between the articular surfaces at diarthrodial
Synovial fluid, synovia.
Synovial membrane, the dense and very smooth connective
tissue membrane which secretes synovia and surrounds
synovial capsules and other synovial cavities.