1 an unexpected or astonishing event, fact, or thing : the announcement was a complete surprise.
• a feeling of mild astonishment or shock caused by something unexpected : much to their surprise, there was more to celebrate.
• [as adj. ] denoting something made, done, or happening unexpectedly : a surprise wedding.
As their parents were laughing and crying and hugging and taking it all in, the bride ran upstairs to change and WHOOSH the graduation-turned-wedding was underway.