to celebrate / to officiate
che-le-BRA-re
Celebrare has both a secular (to celebrate an event) and religious (to officiate mass) meaning. More formal than 'festeggiare'.
Il sacerdote celebra la messa di Natale.
The priest celebrates Christmas mass.
Celebriamo i 100 anni di questo ristorante storico.
We celebrate the 100 years of this historic restaurant.