having no embellishments, extra equipment, elaborate packaging, etc.; plain; simple; down-to-earth: I want a plain-vanilla car without a lot of chrome trim.
Origin: in allusion to vanilla ice cream, taken to be the most basic flavor
Of or relating to the uncomplicated version of a particular type of security. For example, a plain-vanilla derivative is typically exchange-traded and void of bells and whistles. Likewise, a plain-vanilla bond is not convertible and cannot be called.
[pleyn-vuh-nil-uh] 
