indomethacinPronunciation: /ˌɪndəʊˈmɛθəsɪn/Definition of indomethacin noun [mass noun] Medicine a compound with anti-inflammatory, antipyretic, and analgesic properties, used chiefly to treat rheumatoid arthritis and gout. Chemical formula: C19H16NO4Cl Origin: 1960s: from indo(le) + meth(yl) + ac(etic) + -in1indomethacin in other Oxford dictionaries Definition of indomethacin in the US English dictionary