n (countable) Any tropical, climbing orchid of the genus Vanilla (especially (taxlink|Vanilla planifolia|species)), bearing podlike fruit yielding an extract used in flavoring food or in perfumes.
n (countable) The fruit or bean of the vanilla plant.
n (uncountable) The extract of the fruit of the vanilla plant.
n (uncountable) Any artificially produced homologue of vanilla extract, principally vanillin produced from lignin from the paper industry or from petrochemicals.
a (colloquial) By association with vanilla as the "plain" flavour of ice cream: the standard, plain, default, unmodified, basic.