[exidemic, -al Errors for epidemic, -ical, due to the similarity of x and p in 16th and 17th cent. hands. 1608Topsell Serpents 76 A certaine token..that some exidemicall [ed. 1658 epidemicall], generall pestilence or plague rageth amongst them.1847–78Halliwell, Exidemic (citing Hall).]