Celebratory

to observe (a day) or commemorate (an event) with ceremonies or festivities:
to celebrate Christmas; to celebrate the success of a new play.
to make known publicly; proclaim:
The newspaper celebrated the end of the war in red headlines.
to praise widely or to present to widespread and favorable public notice, as through newspapers or novels:
a novel celebrating the joys of marriage; the countryside celebrated in the novels of Hardy.
to perform with appropriate rites and ceremonies; solemnize:
to celebrate a marriage.
to observe a day or commemorate an event with ceremonies or festivities.
to perform a religious ceremony, especially Mass or the Lord’s Supper.
to have or participate in a party, drinking spree, or uninhibited good time:
You look like you were up celebrating all night.
Contemporary Examples

verb
to rejoice in or have special festivities to mark (a happy day, event, etc)
(transitive) to observe (a birthday, anniversary, etc): she celebrates her ninetieth birthday next month
(transitive) to perform (a solemn or religious ceremony), esp to officiate at (Mass)
(transitive) to praise publicly; proclaim
adj.

1855, from celebrate + -ory.
v.

mid-15c., originally of the Mass, from Latin celebratus “much-frequented; kept solemn; famous,” past participle of celebrare “assemble to honor,” also “to publish; sing praises of; practice often,” originally “to frequent in great numbers,” from celeber “frequented, populous, crowded;” with transferred senses of “well-attended; famous; often-repeated.” Related: Celebrated; celebrating.