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.