According to Gartner, Shared services or a shared services center (SSC) is a dedicated unit (including people, processes and technologies) that is structured as a centralized point of service and is focused on defined business functions. These functions are supported by IT and IT services for multiple business units within the enterprise.
The term “Shared Services” defines an operational model that involves centralizing the specific administrative functions of a company that were once performed in separate divisions or locations. In a shared service center, typical `back office’ functions—such as Accounts Payable (AP) Accounts Receivable (AR) or IT—are centralized. For example, instead of having a separate AP, AR or IT department in every state/country a company operates in, an enterprises can choose to have a regional or global Accounts Payable shard services center.