The Common Terminology Specification (CTS) specification defines a set of platforms- and implementation-neutral Application Programming Interface (API) calls that are used to access terminology content for the HL7 Version 3 programming environment. The specification defines common mechanisms to access disparate terminological content in a consistent, reproducible fashion. Software clients that have been programmed using this API will be able to access any compliant back-end service without requiring knowledge of the underlying data structures and low-level access mechanisms. Similarly, services that implement this API may be utilized by any compliant client. The CTS specification defines the interface elements in Unified Modeling Language (UML), and the actual API is specified using the ISO 14750 Interface Definition Language (IDL).