(+ object)
1 : to exist or be done in order to remind people of (an important event or person from the past)
The festival commemorates the town’s founding.
The plaque commemorates the battle that took place here 200 years ago.
2 : to do something special in order to remember and honor (an important event or person from the past)
Each year on this date we commemorate our ancestors with a special ceremony.
All of the director’s films will be shown to commemorate (=observe) the 50th anniversary of his death.