Thursday after Trinity Sunday; first celebrated in 1246 WordNet 3.0 & Open English WordNet

The Feast of Corpus Christi, also known as the Solemnity of the Most Holy Body and Blood of Christ, is a Christian liturgical solemnity celebrating the Real Presence of the Body and Blood, Soul and Divinity of Jesus in the elements of the Eucharist; it is observed by the Latin Church, in addition to certain Western Orthodox, Lutheran, and Anglican churches. Wikipedia

A Christian solemnity which honors the institution of the Holy Eucharist Wikipedia Disambiguation

Catholic feast day, public holiday in some countries Wikidata

A feast day in honor of the Eucharist, observed by Roman Catholics and high-church Anglicans on the Thursday after Trinity Sunday. Wiktionary