Plain vanilla is an adjective describing the simplest version of something, without any optional extras, basic or ordinary.[1] In analogy with the common ice cream flavour vanilla, which became widely and cheaply available with the development of artificial vanillin flavour.[2] Certain financial instruments, such as put options or call options, are often described as plain vanilla options. The opposite of plain vanilla options are exotic options.[3]
Vanilla has become a synonymous with 'plain'- perhaps most vanilla ice cream is flavoured with fake vanilla extract