ar·thri·tis (är-thr??t?s)n. Any of several diseases of the joints, such as osteoarthritis or rheumatoid arthritis, characterized by pain, swelling, and often stiffness, and usually involving inflammation.ar·thrit?ic (-thr?t??k) adj. & n.ar·thrit?i·cal·ly adv.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.arthritis (????ra?t?s) n (Pathology) inflammation of a joint or joints characterized by pain and stiffness of the affected parts, caused by gout, rheumatic fever, etc. See also rheumatoid arthritis[C16: via Latin from Greek: see arthro-, -itis] arthritic adj, nUsage: Rather than talking about an arthritic or arthritics, it is better to talk about a person with arthritis and people with arthritisCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ar?thri?tis (?r??ra? t?s) n. inflammation of one or more joints. [1535?45;