The Collaborative International Dictionary of English v.0.48:

Arthritis \Ar*thri"tis\ ([aum]r*thr[imac]"t[i^]s), n. [L., fr.
   Gr. 'arqri^tis (as if fem. of 'arqri`tis belonging to the
   joints, sc. no`sos disease) gout, fr. 'a`rqron a joint.]
   (Med.)
   Any inflammation of the joints, including the gout. A variety
   of forms of arthritis are recognized, some of which (such as
   rheumatoid arthritis, also called arthritis deformans and
   arthritis nodosa) are chronic and progressive, and lead to
   incapacitation and deformity.
   [1913 Webster +PJC]