Entry 2 senses · 2 variants Webster, 1913 Ergotism /ẽrg'-ət-ĭzˌ-əm/ · Er·go·tism · IPA /ˈɜrɡətˌɪzəm/ n. n. 01 n. A logical deduction. 1. A logical deduction.[Obs.] 02 n. A diseased condition produced by eating rye affected with the ergot fungus. 1. A diseased condition produced by eating rye affected with the ergot fungus.(Med.)