The Collaborative International Dictionary of English v.0.48:
Major general \Ma"jor gen"er*al\ An officer of the army holding a rank next above that of brigadier general and next below that of lieutenant general, and who usually commands a division or a corps. [1913 Webster]Bouvier's Law Dictionary, Revised 6th Ed (1856):
MAJOR GENERAL. A military officer, commanding a division or number of regiments; the next in rank below a lieutenant general.