Definition for Convection
From Biology Forums Dictionary
1) The transfer of heat by the movement of air or water next to the body.
2) Convection is the process by which heat is transferred from one part of a fluid to another by movement of the fluid itself. There are two methods in which this can be carried out. One is by natural convection, in which movement occurs as a result of gravity, the hot part of the fluid expands, become less dense and is displaced by the colder denser part of the fluid as this drops below it. Forced convection is where hot fluid is transferred from one region to another by a pump.