Dictionary.net

Condition seemingly paradoxal that a consumer item, deemed essential to the community, is in greater demand when its price rises, and in less demand when the price falls. This occurred to corn in 19th century England and to the alcoholic beverage 'shochu' in modern Japan. Both items were considered 'essential' by a section of consumers. To maintain the same level of consumption the consumers spend more of their income as its price increases. They buy more of the same good because they cannot afford the more expensive substitutes. When its price falls the opposite happens. This paradox was first studied and reported by UK economist Sir Robert Giffen (1837-1910).