Definition of mehndi:
(n) :
(uncountable) A temporary skin decoration made with henna.
(n) :
(uncountable) The practice of applying such decoration, typically as part of a bride or groom's preparations for a wedding.
(n) :
(uncountable) The preparation of this plant used for dyeing.
(n) :
(countable) A henna plant (Lawsonia inermis).