It can be a cycling club, a group of friends, or a social riding group you are a part of.
Clubs/Groups are different from 'Workplaces Profiles'. If you are a group of employees, you should create a Workplace Profile instead. Find out how to do that here.
However, if you are a group of people associated with a workplace, but you are not all employees of the workplace, then a Club/Group is the perfect option. For example, if you are a group of employees plus other associated folks who are not employed there (e.g. board members, family and friends, etc.), you should create a Club/Group rather than a Workplace Profile.
Clubs/Groups do not compete based on points during challenges, and can be used year-round, including outside of specific challenges and campaigns.