An Etymological Dictionary of Astronomy and Astrophysics

A process that occurs in a medium where a → temperature gradient exists:

dQ = -κ(dT/dx)dA.dt, where dQ is the amount of heat passing through the time dt across an area dA in the direction of the normal x to this area and toward the reduction in temperature, κ is the → thermal conductivity, and (dT/dx) the temperature gradient.

See also: → thermal; → conduction.