ˈ ̷ ̷ˌ ̷ ̷ noun
1.
a. also soapbark tree : a Chilean tree ( Quillaja saponaria ) with shining leaves and terminal white flowers
b. : the bark of the soapbark tree that because of its saponin content yields a soapy lather and is used in cleaning and in emulsifying oils — compare quillaic acid
2. also soapbark tree : any of several tropical American trees or shrubs of the genus Pithecolobium (as P. bigeminum ) having saponaceous bark