The New Palgrave Dictionary of Economics, 2nd edition, edited by Steven N. Durlauf and Lawrence E. Blume, 2008. Contains over 1,850 articles by more than 1,500 of the world's leading economists. Updated quarterly.
Based on The New Palgrave: A Dictionary of Economics, edited by Eatwell, Milgate and Newman, 1987, but with 80% new material. 1987 edition also included; can be searched separately or together with the 2008 edition.