vanilla (n.)
1660s, "pod of the vanilla plant," from Spanish vainilla "vanilla plant," literally "little pod," diminutive of vaina "sheath," from Latin vagina "sheath of an ear of grain, hull of a plant" (see vagina). So called from the shape of the pods. European discovery 1521 by Hernando Cortes' soldiers on reconnaissance in southeastern Mexico. Meaning "flavoring extracted from the vanilla bean" is attested by 1728. Meaning "conventional, of ordinary sexual preferences" is 1970s, from notion of whiteness and the common choice of vanilla ice cream.