Liturgy
WordNet
noun
(1) A rite or body of rites prescribed for public worship
(2) A Christian sacrament commemorating the Last Supper by consecrating bread and wine
WiktionaryText
Etymology
From Latin liturgia, from λειτουργία < λειτ-, from λαός, people + -ουργός < ἔργον, work (the public work of the people done on behalf of the people)