Capacity planning is the process of determining the production capacity needed by an organization to meet changing demands for its products. In the context of capacity planning, "capacity" is the maximum amount of work that an organization is capable of completing in a given period of time.
Capacity is defined as the capability of a worker, machine, work center, plan or organization to produce output per period of time. Capacity is a rate of doing work, not the quantity of work done.
(Source : http://www.apicsforum.com/ebook/5b._capacity_management)
Capacity available is the capacity of a system or resource to produce a quantity of output in a given time period.
Load is the amount of released and planned work assigned to a facility for a particular time period. It is the sum of all the required capacities.
Oracle Capacity lets you calculate your capacity load ratio by resource or production line. It ensures that you have sufficient capacity to meet your production requirements.
Oracle Capacity provides you with two levels of capacity planning:
Rough cut capacity planning (RCCP) to validate your master schedules
Detailed capacity requirements planning (CRP) to validate your MRP plans