To heat again.

heat again; "Please reheat the food from last night"

The application of sensible heat to supply air that has been previously cooled below the temperature of the conditioned space by wither mechanical refrigeration or the introduction of outdoor air to provide cooling.

To revive; to cheer; to cherish.

An option on some units that allows food warm-up at the touch of a button. Some models employ a cooking sensor for this; others offer pre-set times.