n. [ L. convectio, fr. convehere to bring together; con- + vehere to carry. ] 1. The act or process of conveying or transmitting. [ 1913 Webster ]
2. (Physics) A process of transfer or transmission, as of heat or electricity, by means of currents in liquids or gases, resulting from changes of temperature and other causes. [ 1913 Webster ]
Liquids are generally heated by convection -- when heat is applied from below. Nichol. [ 1913 Webster ]