commemoration (n.)

late 14c., "a calling to mind," also "service or church festival commemorating something," from Old French comemoration, from Latin commemorationem (nominative commemoratio) "reminding, mention," noun of action from past participle stem of commemorare "to call to mind," from com-, here as an intensive prefix (see com-), + memorare "to remind," from memor "mindful of" (from PIE root *(s)mer- (1) "to remember").