"Go Bag" -- A kit designed around "I expect to leave this place on short or no notice to do a thing." I travel quite a bit for my job, and my overnight bag fits this description. I can be out the door for a 1-4 night trip in under five minutes. I have another bag set up for IT support. While that's not my job any more, every so often I am doing something for work or for a friend or relative, and it's convenient for me to have those things in its own bag.

"Bail Out Bag" -- A kit designed around "I may have to leave this conveyance that I'm in abruptly." A kayaker may have fire-makings, communications, and first aid gear, for example.

"Bug Out Bag" -- Here I've seen a lot of different definitions. Mine is a kit designed around "I may have to leave this place abruptly." I do not maintain one of these. You may look at my car-based emergency kit and call it a Bug Out Bag. Neither I nor the bag would be offended, even though that's not how I think of it.

These are my definitions for me and my situation and use cases, yours may be different.