Definition of mad-apple in US English:

mad-apple

noun

  • 1The fruit of the eggplant or aubergine, Solanum melongena; the plant itself. Occasionally also (formerly also in plural): any of certain other plants of the genus Solanum, especially S. linnaeanum. Now archaic.

  • 2The thorn apple, Datura stramonium.

Origin

Late 16th century; earliest use found in Henry Lyte (1529–1607), botanist and antiquary. From mad + apple, after post-classical Latin malum insanum from Italian † mela insana variant, after mela apple and insano, of melanzana, † melenzana, ultimately from Persian bādingān.

Pronunciation

mad-apple

/ˈmadˌapl/