vanilla [M17th] This word for a flavouring is from Spanish vainilla ‘pod’, a diminutive of vaina ‘sheath, pod’, from Latin vagina ‘sheath’, also source of vagina [L17th]. The spelling change, dropping the ‘i’, was due to association with French vanille. Since the 1970s the word has been used to mean ‘plain, basic, conventional’ from the popular perception of vanilla as the basic or usual flavour of ice-cream.