An environmentally conditioned work space that is partially equipped with information systems and telecommunications equipment to support relocated operations in the event of a significant disruption.
Source: NIST CNSSI 4009-2015 from NIST SP 800-34 Rev. 1
NIST SP 800-34 Rev. 1 under Warm Site
An alternate processing site which is equipped with some hardware, and communications interfaces, electrical and environmental conditioning which is only capable of providing backup after additional provisioning, software or customization is performed.
A warm site is a type of disaster recovery site that provides the necessary infrastructure for a business to continue operations after a disaster. It typically includes basic hardware such as servers, storage, and networking equipment, as well as power, cooling, and connectivity. The warm site is ready to be used in the event of a disaster, but the business must still provide the software and data needed to resume operations.