What is a co-op apartment?

Question

What is a co-op apartment?

Answer 1

With a co-op you own shares in the corporation which owns the building.  In return, you are granted a proprietary lease which gives you the right to use and occupy a specific unit.

It differs from a condo in that with a condo, you own your own unit and a percentage of the common area.  

Answer 2

A housing cooperative is a legal entity—usually a corporation—that owns real estate, consisting of one or more residential buildings. Each shareholder in the legal entity is granted the right to occupy one housing unit, sometimes subject to an occupancy agreement, which is similar to a lease.