Commas before conjunctions (e.g., and, or, but). When a word like and, or, and but (called conjunctions) joins two standalone sentences, you should put a comma before it. (The real name for a standalone sentence within a longer sentence is independent clause .).Words like and, or, and but are known as conjunctions.earch. When a word like and, or, and but (called conjunctions) joins two standalone sentences, you should put a comma before it. (The real name for a standalone sentence within a longer sentence is independent clause .).
1. a polygon having five angles and five sides. 2. the Pentagon, a. a building in Arlington, Va., built in the form of a pentagon and containing most of the offices of the U.S. Department of Defense. b. the U.S. Department of Defense; the U.S. military establishment. [1560â70; < Late Latin pentagÅnum < Greek pentÃ¡gÅnon, n. use of neuter of pentÃ¡gÅnos five-angled.
The Pentagon. The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia, across the Potomac River from Washington, D.C. As a symbol of the U.S. military, The Pentagon is often used metonymically to refer to the U.S. Department of Defense. The Pentagon was designed by American architect George Bergstrom, and built by general contractor John McShain of Philadelphia. Ground was broken for construction on September 11, 1941, and the building was dedicated o