The Collaborative International Dictionary of English v.0.48:

meals on wheels \meals on wheels\, meals-on-wheels
\meals-on-wheels\n.
   A program that delivers hot meals to persons, such as the
   elderly or disabled, who are confined to their homes and
   unable to cook for themselves; also, the meals thus
   delivered. Such programs are usually conducted by
   governmental or charitable organizations.
   [PJC]