A “go bag” is typically a pack or bag that is loaded with the essentials someone might need to survive if they have to leave where they are in a hurry.  I differentiate the go bag from the bug out bag, considering the bug out bag to have more supplies to better sustain me for several days, while the go bag is to get me out of the immediate situation.
The Gerber Go Bag is a recent introduction to the market and combines a Maxpedition bag with various equipment.