Solemnity

In the liturgical calendar of the Roman Rite, a solemnity is a feast day of the highest rank celebrating a mystery of faith such as the Trinity, an event in the life of Jesus, his mother Mary, his earthly father Joseph, or another important saint. The observance begins with the vigil on the evening before the actual date of the feast. Unlike feast days of the rank of feast (other than feasts of the Lord) or those of the rank of memorial, solemnities replace the celebration of Sundays outside Advent, Lent, and Easter (those in Ordinary Time).^[1]

The word comes from postclassical Latin sollemnitas, meaning a solemnity, festival, celebration of a day.^[2]