IPA: //ˌsɛlɪˈbreɪtəri//
KK: /sɛlɪˈbreɪtəri/
Relating to or expressing joy and happiness during a special event or occasion.
The party had a celebratory atmosphere as everyone gathered to toast the newlyweds.
Celebratory → It is formed from "celebratus" (meaning celebrated) and the suffix "-ory" (meaning relating to or characterized by). The word "celebratory" refers to something that is characterized by celebration or is intended to celebrate.
Think of something that is 'characterized by celebration' — 'celebratus' means celebrated, and '-ory' indicates a relation. This helps you remember that celebratory is all about celebrating.