1) Ceremonial 2) Ceremonial occasion 3) Ceremony 4) Commemorating 5) Intended as a commemoration 6) Like some plaques 7) Observance 1) Commemorating 2) Honorary 
• (a.) Tending or intended to commemorate.
objects inscribed or decorated to commemorate an event or a person.
A coin with a design honoring a person, place or event in history.
A piece issued to mark, honor or observe an anniversary, other event, place or person, or to preserve its memory.
Com·mem'o·ra·tive adjective Tending or intended to commemorate. 'A sacrifice commemorative of Christ's offering up his body for us.' Hammond. « An inscription commemorative of his victory. Sir G. C. Lewis. » 
[adj] - intended as a commemoration
commemorating adjective intended as a commemoration; `a commemorative plaque`
serving to commemorate: a commemorative monument; a commemorative dinner. · (of a coin, medal, or postage stamp) issued to commemorate a historical event, to honor the memory of a personage, etc.