tenosynovitis vs synovitis

tenosynovitis and synovitis both are nouns.

Word	Noun	Adjective	Verb	Adverb
tenosynovitis	Yes	No	No	No
synovitis	Yes	No	No	No

As nouns, synovitis is a hypernym of tenosynovitis; that is, synovitis is a word with a broader meaning than tenosynovitis:

tenosynovitis: inflammation of a tendon and its enveloping sheath
synovitis: inflammation of the synovial membrane that lines a synovial joint; results in pain and swelling

Other hypernyms of tenosynovitis include tendinitis, tendonitis, tenonitis.

tenosynovitis (noun)	synovitis (noun)
inflammation of a tendon and its enveloping sheath	inflammation of the synovial membrane that lines a synovial joint; results in pain and swelling