In economics, a luxury good (or upmarket good) is a good for which demand increases more than what is proportional as income rises, so that expenditures on the good become a more significant proportion of overall spending. Luxury goods are in contrast to necessity goods, where demand increases proportionally less than income.[1] Luxury goods is often used synonymously with superior goods.
[...] as the consumer gets more income, he consumes more of both goods but proportionally more of one good (the luxury good) than of the other (the necessary good).