Commemoration or celebration — acts or ceremonies to honor or remember an event or person.
戦没者を記念して追悼式が行われた。
A memorial service was held to commemorate the war dead.
結婚十周年を記念して旅行に出かけた。
We went on a trip to celebrate our tenth wedding anniversary.
創立記念として式典とレセプションが催された。
A ceremony and reception were held to commemorate the founding.
A memento or souvenir — an object kept to remember an event or occasion.
旅行の記念に小さな置物を買った。
I bought a small ornament as a souvenir from the trip.
入学の記念にクラスで写真を撮った。
We took a class photo as a keepsake for entering school.