There are six meanings listed in oed's entry for the noun requiem, two of which are labelled obsolete. See รขโ‚ฌหœmeaning & useรขโ‚ฌโ„ข for definitions, usage, and quotation evidence. A mass (= a christian ceremony) at which people honour and pray for a dead person:

Learn more. Definition of requiem noun in oxford advanced learner's dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more. A requiem (latin: Rest) or requiem mass, also known as mass for the dead (latin: Missa pro defunctis) or mass of the dead (latin: Missa defunctorum), is a mass of the catholic church offered for the รขโ‚ฌยฆ

Rest) or requiem mass, also known as mass for the dead (latin: Missa pro defunctis) or mass of the dead (latin: Missa defunctorum), is a mass of the catholic church offered for the รขโ‚ฌยฆ