A graph showing the degree of inequality in income and wealth in a given population or an economy. It is a rigorous way to measure income inequality.  

• In this method (for example), personal incomes in an economy are arranged in increasing order; the cumulative share of total income is then plotted against the cumulative share of the population.  
• The curve’s slope is thus proportional to per capita income at each point of the population distribution.  

• In the case of complete equality of income, the lorenz curve will be a straight line and with greater curvature the inequality rises proportionally–the Gini Coefficient measures this inequality. 

Source: TMH Ramesh Singh