Definition of "firebase"

They had each set up a one-tank firebase, and become the center of a small community. Behind the sandbagged fort that each crew had built, a cluster of refugee huts and sprung up, and now, as the company drove by, these were the scenes of farewells.

1986, Ralph Zumbro, “Road to Pleiku”, in Tank Sergeant, New York, N.Y.: Pocket Books, page 102

US ground troop operations in the A Shau Valley were strengthened by fire support bases strategically located throughout the area. Firebase names like Eagle's Nest, Berchtesgaden, and Currahee evoked connections to the 101st Airborne's storied past during WWII. […] Our assignment after Hamburger Hill was at Firebase Airborne. […] The firebase housed batteries of 60mm and 81mm mortars, as well as 105mm and 155mm artillery pieces manned by units of the 211st and 319th Field Artillery.

2005, Arthur Wiknik, Jr., “The A Shau Valley”, in Nam-sense: Surviving Vietnam with the 101st Airborne Division, Drexel Hill, Pa., Newbury, Berkshire: Casemate Publishers, page 55

Firebase Birmingham seemed pretty nice after our recent field experiences and it was good to be back. It was really great to be able to take a shower every day, wear relatively clean fatigues and eat hot chow most of the time. The food on Birmingham and the rest of the firebases was generally pretty good.

2008, John A. Nesse, “Firebase Gastogne”, in The Ghosts of Thua Thien: An American Soldier's Memoir of Vietnam, Jefferson, N.C.: McFarland & Company, page 79