For the purpose of the Revised 508 Standards, the terms defined in E103.4 have the indicated meaning.
Agency
Any agency or department of the United States as defined in 44 U.S.C. 3502, and the United States Postal Service.
Alteration
A change to existing ICT that affects interoperability, the user interface, or access to information or data.
Application
Software designed to perform, or to help the user to perform, a specific task or tasks.