The first dictionary definitions of essential are ‘vital’, ‘absolutely necessary’. However there is one place where we see the word every day when this is not its meaning, even if the users of the word would like us to think it is. Manufacturers of soaps, shower gels, shampoos and the like are keen to tell us when they have added “essential oils” to their products. There are alternative names for these oils: volatile oils or ethereal oils, but of course these names would not serve the ends of the manufacturers – they do not give the impression that without the oils we will die!
All that essential oils do is add a pleasant smell to the product: “essential oil – an oil present in and having the characteristic odour of a plant etc., from which it can be obtained by distillation” (Oxford English Reference Dictionary). Essential in this sense is the adjective formed from essence in its subsidiary meaning: “an extract obtained by distillation etc., especially a volatile oil; a perfume or scent, especially made from a plant or animal substance”.
Essential? I don’t think so!