- noun the process by which hot air rises and cool air descends
- The movement of a gas or liquid upward as it is heated and downward as it is cooled. The movement is caused by a change in density.
- The transmission of energy or matter through a medium, which is itself moved. For instance, in convection cooling, the air transferring the heat moves along with the heat. This contrasts with conduction, where the medium itself is not moved as a whole, and with radiation, where waves or particles are emitted.