Sentence:  Willow Run , General Electric 's enormous installations at Louisville and Syracuse , the <WSD>Pentagon</WSD> , Boeing in Seattle , Douglas and Lockheed in Los Angeles , the new automobile assembly plants everywhere - none of these is substantially served by any sort of conventional mass rapid transit . 
Meaning of the word marked with <WSD> tags:  a government building with five sides that serves as the headquarters of the United States Department of Defense