jalapPronunciation: /ˈdʒaləp, ˈdʒɒləp/Definition of jalap noun [mass noun] a purgative drug obtained chiefly from the tuberous roots of a Mexican climbing plant. This drug is obtained from Ipomoea purga, family Convolvulaceae Origin: mid 17th century: from French, from Spanish (purga de) Jalapa (see Jalapa)jalap in other Oxford dictionaries Definition of jalap in the US English dictionary