solemnize

To celebrate or observe with dignity and gravity: synonym: observe.

To perform (a marriage, for example) with formal ceremony.

To make serious or grave.

Solemnization.

To perform annually; perform as the year comes round.

To honor by ceremonies; celebrate: as, to solemnize the birth of Christ.

To perform with ritual ceremonies, or according to legal forms: used especially of marriage.

To render solemn; make serious, grave, and reverential: as, to solemnize the mind for the duties of the sanctuary.

Also spelled solemnise.

To perform with solemn or ritual ceremonies, or according to legal forms.