Common term for tenant-based keys

Assume the following schema: ID  | TENANT | TENANT_CUSTOM_ID 346 | 101    | 1 347 | 102    | 1 348 | 101    | 2 349 | 101    | 3 350 | 101    | 4 351 | 102    | 2 352 | 103    | 1 **What is another name (or the proper classification) for TENANT_CUSTOM_ID?** Perhaps something along the lines of a surrogate key? The purpose of this key is to make each tenant have their own numbering system instead of knowing that their records are mixed with all other tenants on the same tables.