The Collaborative International Dictionary of English v.0.48:

Nephritis \Ne*phri"tis\, n. [L., fr. Gr. nefri^tis (sc. ?), fr.
   nefro`s a kidney.] (Med.)
   An inflammation of the kidneys.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nephritis
    n 1: an inflammation of the kidney [syn: nephritis, Bright's
         disease]

Moby Thesaurus II by Grady Ward, 1.0:

138 Moby Thesaurus words for "nephritis":
   adenoiditis, adrenitis, appendicitis, arteritis,
   arthritis deformans, arthritis fungosa, arthritis pauperum,
   atrophic arthritis, atrophic inflammation, blennorrhagic arthritis,
   brain fever, bronchitis, bunion, bursitis, capillaritis, carditis,
   catarrh, catarrhal inflammation, cerebellitis, cerebral meningitis,
   cerebritis, cerebrospinal meningitis, chronic infectious arthritis,
   chronic inflammation, cirrhotic inflammation, climactic arthritis,
   clitoritis, colitis, collagen disease, conjunctivitis, cystitis,
   degenerative arthritis, diffuse inflammation, encephalitis,
   endocarditis, enteritis, equine encephalomyelitis,
   exudative inflammation, fibroid inflammation, focal inflammation,
   gastritis, gingivitis, glomerulonephritis, glossitis,
   gonococcal arthritis, gonorrheal arthritis, gonorrheal rheumatism,
   gout, gouty arthritis, hemophilic arthritis, hepatitis,
   hyperplastic inflammation, hypertrophic arthritis,
   hypertrophic inflammation, infectional arthritis,
   infectious hepatitis, inflammation, irritable bowel syndrome,
   kidney stone, laryngitis, lumbago, lumbar rheumatism, mastoiditis,
   meningitis, menopausal arthritis, metastatic inflammation,
   metritis, milk leg, mucous colitis, mumps meningitis, myelitis,
   necrotic inflammation, nephrolithosis, nephrosis, neuritis,
   obliterative inflammation, ophthalitis, ophthalmia, orchitis,
   osseous rheumatism, osteitis, osteoarthritis, osteomyelitis,
   otitis, ovaritis, paradental pyorrhea, penitis, pericarditis,
   periodontitis, peritonitis, pharyngitis, phlebitis, podagra,
   proliferative arthritis, prostatitis, pyonephritis, pyorrhea,
   pyorrhea alveolaris, reactive inflammation, renal calculus,
   renal hematuria, rheumatism, rheumatiz, rheumatoid arthritis,
   rhinitis, sclerosing inflammation, seroplastic inflammation,
   serous inflammation, serum hepatitis, simple inflammation,
   sinusitis, spastic colon, specific inflammation,
   subacute rheumatism, suppurative arthritis,
   suppurative inflammation, syphilitic arthritis, tennis elbow,
   testitis, thrombophlebitis, tonsilitis, torticollis,
   toxic inflammation, traumatic inflammation, tuberculous arthritis,
   tuberculous rheumatism, ulcerative colitis, uratic arthritis,
   uremia, ureteritis, urethral arthritis, urethritis, uteritis,
   vaginitis, vertebral arthritis, visceral rheumatism, vulvitis,
   wryneck