Note: Capacity is often used in an interchangeable way with Capability. Moreover, Capacity building is often used in an interchangeable way with Capacity development.
Other International Definitions
Capacity building is a process that supports only the initial stages of building or creating capacities and assumes that there are no existing capacities to start from. 
Capacity development is defined as the process whereby people, organizations and society as a whole unleash, strengthen, create, adapt and maintain capacity over time. 
Capacity development: The process by which people, organizations and society systematically stimulate and develop their capacities over time to achieve social and economic goals, including through improvement of knowledge, skills, systems, and institutions.