An Etymological Dictionary of Astronomy and Astrophysics

A vector quantity that depends on the distribution of temperature in three dimensions with respect to a given point. The magnitude and orientation of the maximum thermal gradient are given by:

∇T = (∂T/∂x)i + (∂T/∂y)j

• (∂T/∂z)k, where T is the temperature distribution function in three dimensions, and i, j, and k are the unit vectors along the x, y, and z axes defining the temperature field.
  Same as → temperature gradient.

See also: → thermal; → gradient.