a white powder, CHNO, used as an analgesic, as for the relief of rheumatoid arthritis
See phenylbutazone in American Heritage Dictionary 4
(fĕnˌəl-byo͞oˈtə-zōnˌ)
noun
A white or light yellow compound, C19H20N2O2, formerly used as an anti-inflammatory and analgesic drug in the treatment of arthritis, bursitis, and gout.