; (C) the ports of entry along the areas described in subparagraph (A); and (D) the transit zone. (8) Persistent wide area maritime surveillance (pwams) The term persistent wide area maritime surveillance means a system of sensors that provide surveillance and detection to aid in the classification and identification of surface and subsurface vessels of diverse sizes out to 200 nautical miles from shore to prevent terrorism, enhance security, secure the United States border, and enforce immigration laws. (9) Secretary The term Secretary means the Secretary of Homeland Security. (10) Transit zone The term transit zone has the meaning given such term in section 1092(a)(8) of the National Defense Authorization Act for Fiscal Year 2017 ( 6 U.S.C. 223(a)(8) ). (11) Unmanned aircraft system The term unmanned aircraft system has the meaning given such term in section 44801 of title 49, United States Code.