Support the socializing between colleagues.
After-work gatherings were invented in the Anglo-Saxon world and describe a celebration or event in the professional environment, that starts directly after the actual working day and part or the entire workforce participates. After work can take place on any day within the week, as you usually start around 6pm and also usually don't go into the night out of consideration for the next workday.
In theory, any casual party held in a professional setting can be considered as an after-work event. This could be a company party or a team party, for example. You may be celebrating a successfully completed project or the successful pitch of a project and want to spread motivation and good humor through this event at the same time.