Warm Site

An environmentally conditioned workspace that is partially equipped with information systems and telecommunications equipment to support relocated operations in the event of a significant disruption.
SOURCE: SP 800-34

Backup site which typically contains the data links and preconfigured equipment necessary to rapidly start operations, but does not contain live data. Thus commencing operations at a warm site will (at a minimum) require the restoration of current data.
SOURCE: CNSSI-4009