| Noun | 1. | Department of Homeland Security - the federal department that administers all matters relating to homeland security executive department - a federal department in the executive branch of the government of the United States Federal Emergency Management Agency, FEMA - an independent agency of the United States government that provides a single point of accountability for all federal emergency preparedness and mitigation and response activities Immigration and Naturalization Service, INS - an agency in the Department of Justice that enforces laws and regulations for the admission of foreign-born persons to the United States Federal Law Enforcement Training Center, FLETC - a center in the Department of that trains law enforcement professionals for more than seventy federal agencies Secret Service, SS, United States Secret Service, US Secret Service, USSS - the United States intelligence agency that protects current and former presidents and vice presidents and their immediate families and protects distinguished foreign visitors; detects and apprehends counterfeiters; suppresses forgery of government securities and documents |