The Collaborative International Dictionary of English v.0.48:

Chantry \Chant"ry\, n.; pl. Chantries. [OF. chanterie, fr.
   chanter to sing.]
   1. An endowment or foundation for the chanting of masses and
      offering of prayers, commonly for the founder.
      [1913 Webster]

   2. A chapel or altar so endowed. --Cowell.
      [1913 Webster]