Here are some synonyms for "commemorate":
* Celebrate
* Remember
* Honor
* Mark
* Observe
Here are some examples of how "commemorate" can be used in a sentence:
* "The city held a parade to commemorate the 50th anniversary of its founding."
* "A statue was erected in the park to commemorate the fallen soldiers."
* "The family gathered to commemorate the grandfather's birthday."
* "The museum is hosting an exhibition to commemorate the artist's life and work."
Essentially, "commemorate" means to keep something alive in our memories through actions or symbols.