Definition of "mimosa"

(botany) A plant belonging to the genus Mimosa usually found in tropical climates, their leaves are usually prickly and sensitive to touch or light, and have small white or pink flowers.  examples

Certain plants of the genus Albizia (silk tree, pink siris).  examples

Certain plants of the genus Acacia.  examples

A cocktail consisting of half champagne and half orange juice.  examples