solemnity

noun

Etymology: From solemn + -ity, from Middle English solemnity (“observance of formality and ceremony”), frequently in the phrases in solemnity, with solemnity, which from Old French solemnite, from Latin sollemnitās, from sollemnis. (Compare solemn.)

1. The quality of being deeply serious and sober or solemn.

   “the solemnity of a funeral”

   “The stateliness and gravity of the Spaniards shows itself in the solemnity of their language.”

2. An instance or example of solemn behavior; a rite or ceremony performed with reverence.

   “Great was the cauſe; our old ſolemnities / From no blind zeal or fond tradition riſe, / But ſav'd from death, our Argives yearly pay / Theſe grateful honours to the God of Day.”

   “This is the Man after God's Heart, […] by endeavouring, when he aſſiſted at thoſe Solemnities, to perform them with the utmoſt Attention, Alacrity, and holy Warmth of Mind, of which he was capable.”

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. A solemn or formal observance; proceeding according to due form; the formality which is necessary to render a thing done valid.
5. A celebration or festivity.