| 释义 |
necessity A good or service whose consumption by an individual, at a given price, rises less than in proportion to increases in their income. The income elasticity of demand for a necessity is less than one. Necessities are thus goods on which poorer people spend a larger proportion of their incomes than richer people. A necessity is contrasted with a luxury, which is a good or service whose consumption rises more than in proportion to income. See also: Engel curve |