early 15c., "benefit, profit, welfare;" also "a convenient or useful product," from Old French commodité "benefit, profit" (15c.) and directly from Latin commoditatem (nominative commoditas) "fitness, adaptation, convenience, advantage," from commodus "proper, fit, appropriate, convenient, satisfactory," fromcom-, here probably an intensive prefix (seecom-), + modus "measure, manner" (from PIE root *med- "take appropriate measures").
From early 15c. as "article of merchandise, anything movable of value that can be bought or sold." General sense "property, possession" is from c. 1500.