Condo insurance is property coverage designed specifically for condos.
Although homeowners and condo insurance are both written on the HO- form, they do have differences. As with a home, you are responsible for insuring the entire property on your own. With a condo, the owner is usually only responsible for insuring their interest in the entire building. For exmple, if a building is 6 stories and has 22 units, the owner of 1 particular unit is only responsible for insuring their portion of the overall building. The other difference comes in what you need to cover. Each condo association has their own set of rules/bylaws and the owner would need to know what it says in reference to insurance coverage. Some buildings have a master policy that covers more than another building. You would need to know exactly what is in the master policy to see what needs to be covered by the individual owners.
In the end, a condo policy is very similar to a homeowners policy with exceptions and endorsements designed specifically for condo owners.