A reveal/first look is when you do your wedding photos before your ceremony.

This is often done when your ceremony and reception times are close together so that you have time to do all of your photos.

A reveal moment can help calm nerves before your ceremony.
The first look is a great way to capture creative and timely photos while your hair and makeup are fresh and the excitement at its peak.
Completing your photos before your ceremony allows you to enjoy your first moment together. It is also a very intimate first look moment together. You are able to hug and touch and kiss each other, taking in every detail of each other before you become husband and wife.
You also get to mingle and celebrate with your guests during your cocktail hour.