solemnize

verb

Etymology: From Middle English solempnisen, from Old French solemnisier, from Medieval Latin solemnizare, from Latin solemnis.

To make solemn, or official, through ceremony or legal act.
“The couple chose to solemnize their relationship in a secular ceremony, instead of having a wedding.”
“He now is gone to pꝛooue Coſmography, / And as I gueſſe, wil firſt ariue at Rome, / To ſee the Pope, and manner of his court, / And take ſome part of holy Peters feaſt, / That to this day is highly ſolemnizd.”
To make grave, serious, and reverential.
“September 27, 1873, John Campbell Shairp, "Wordsworth's Three Yarrows", in Every Saturday Wordsworth was solemnized and elevated by this his first look on Yarrow.”
“Every Israelite […] arose, solemnized his face, looked towards Jerusalem […] and prayed.”