Disaster Recovery Site - alternate location where operations can continue if the primary site becomes unavailable. Like a backup office ready to use if your main building is damaged.
Financial institutions maintain DR sites in different regions that can fully take over operations within hours of a disaster.
A DR site is an architectural concept (an alternate location/region for running workloads after a disaster), not a single cloud service. Each cloud supports DR sites using region/zone design, replication, backups, and orchestration services.