IPA: /ˈsɛlɪˌbreɪtə/
KK: /ˈsɛlɪˌbreɪtər/
A person who takes part in a celebration or honors a special occasion.
At the party, every celebrator enjoyed the music and dancing.
Celebrator → It is formed from "celebrare" (meaning to celebrate) and "-or" (meaning one who). The word "celebrator" refers to one who celebrates or engages in a celebration.
Think of someone who is 'celebrating' ('celebrare') — the '-or' indicates that this person is the one doing the celebrating.