"Opening celebration" refers to an event or party held to mark the start or grand opening of something, like a new store, building, or event. Full definition
The demand for malls and stores to be up and running in time for peak shopping seasons and grand opening celebrations leaves little room for delays. (nreionline.com)
Look for the exhibit's opening celebration in the coming weeks. (cbhistory.org)
Join us in our colorful opening celebration by helping us paint the studio! (woodstockart.org)