pentagon pentagon /ˈpɛnɪˌgɑːn/

noun

1. A five-sided polygon  ( pentagon )
   a five-sided polygon
    A pentagon has five sides
   A pentagon has five sides
   

 Pentagon

1. () A government building with five sides that serves as the headquarters of the United States Department of Defense  ( The Pentagon , Pentagon )
   a government building with five sides that serves as the headquarters of the United States Department of Defense
    The Pentagon in Washington D.C. is a symbol of the US military's might.
   The Pentagon in Washington D.C. is a symbol of the US military's might.
   
   
2. () (military) the United States military establishment  ( Pentagon )
   (military) the United States military establishment