Definition: To go (somewhere) all together or as a group or in a group; go in a group.
The sign of this ASL verb is a synonym for GO, but it refers to a group of people going together.
It can be also used as an adverb. E.g. "The people went to the parking lot en masse. PEOPLE/\ IX1-plural WILL GO(ix2) IX2 PARKING AREA-ix2 ix1-EN-MASSE-ix2. (Spatial agreement.)