Mass celebrated for the repose of the soul or souls of one or more deceased persons.
A Requiem or Requiem Mass, also known as Mass for the dead or Mass of the dead, is a Mass of the Catholic Church offered for the repose of the soul or souls of one or more deceased persons, using a particular form of the Roman Missal. It is usually celebrated in the context of a funeral (where in some countries it is often called a Funeral Mass). Wikipedia