Mad-apple is a colloquial name for the fruit known as the eggplant. It is a staple in many cuisines, especially in Mediterranean and Middle Eastern dishes. This plant is not actually related to an apple, but it has a similar size and shape. It got the name mad-apple because, in ancient times, people believed that eating eggplants would make them go insane. Synonyms for mad-apple include aubergine, brinjal, guinea squash, and garden egg. These synonyms also refer to the plant and fruit, which are commonly used in various dishes, especially vegetarian and vegan cuisine.