solemnity

noun

1. 1.The quality of being deeply serious and sober or solemn.
2. 2.An instance or example of solemn behavior; a rite or ceremony performed with reverence.
3. 3.A feast day of the highest rank celebrating a mystery of faith such as the Trinity, an event in the life of Jesus, the Virgin Mary, or another important saint.
4. 4.A solemn or formal observance; proceeding according to due form; the formality which is necessary to render a thing done valid.
5. 5.A celebration or festivity.