what is included in CAM

Betty,
Common Area Maintenance (CAM) is the amount of rent charged to tenant in addition to the Base Rent, to maintain the common areas of the property shared by tenants and from which all tenants benefit. Examples include: outdoor lighting, parking lot sweeping, insurance, property taxes, etc.

Amounts charged to tenants for expenses to maintain hallways, restrooms, parking lots, and other Common Areas. Example: In a regional mall, the cost of utilities needed to heat, cool, light, and clean the common areas was allocated to each tenant as common area maintenance, charged back to tenants.
http://www.gregorygarver.com