USS Lexington (hull number CV-2), nicknamed "Lady Lex", was the name ship of her class of two aircraft carriers built for the United States Navy during the 1920s. Originally designed as a Lexington-class battlecruiser, she was converted into one of the Navy's first aircraft carriers during construction to comply with the terms of the Washington Naval Treaty of 1922, which essentially terminated all new battleship and battlecruiser construction. The ship entered service in 1928 and was assigned to the Pacific Fleet for her entire career. Lexington and her sister ship, Saratoga, were used to develop and refine carrier tactics in a series of annual exercises before World War II. On more than one occasion these included successfully staged surprise attacks on Pearl Harbor, Hawaii. The ship's turbo-electric propulsion system allowed her to supplement the electrical supply of Tacoma, Washington, during a drought in late 1929 to early 1930. She also delivered medical personnel and relief supplies to Managua, Nicaragua, after an earthquake in 1931.

Lexington was at sea when the Pacific War began on 7 December 1941, ferrying fighter aircraft to Midway Island. Her mission was canceled and she returned to Pearl Harbor a week later. After a few days, she was sent to create a diversion from the force en route to relieve the besieged Wake Island garrison by attacking Japanese installations in the Marshall Islands. The island surrendered before the relief force got close enough, and the mission was canceled. A planned attack on Wake Island in January 1942 had to be canceled when a submarine sank the oiler required to supply the fuel for the return trip. Lexington was sent to the Coral Sea the following month to block any Japanese advances into the area. The ship was spotted by Japanese search aircraft while approaching Rabaul, New Britain, but her aircraft shot down most of the Japanese bombers that attacked her. Together with the carrier Yorktown, she successfully attacked Japanese shipping off the east coast of New Guinea in early March.

Lexington was quickly refitted in Pearl Harbor at the end of the month and rendezvoused with Yorktown in the Coral Sea in early May. A few days later the Japanese began Operation Mo, the invasion of Port Moresby, Papua New Guinea, and the two American carriers attempted to stop the invasion forces. They sank the light aircraft carrier Shōhō on 7 May during the Battle of the Coral Sea, but did not encounter the main Japanese force of the carriers Shōkaku and Zuikaku until the next day. Aircraft from Lexington and Yorktown badly damaged Shōkaku, but the Japanese aircraft crippled Lexington. A mixture of air and aviation gasoline in her improperly drained aircraft fueling trunk lines (which ran from the keel tanks to her hangar deck) ignited, causing a series of explosions and fires that could not be controlled. Lexington was scuttled by an American destroyer during the evening of 8 May to prevent her capture. The ship's wreck was located on 4 March 2018 by RV Petrel, which was part of an expedition funded by Paul Allen.

Lexington was the fourth US Navy ship named after the 1775 Battle of Lexington, the first battle of the Revolutionary War. She was originally authorized in 1916 as a Lexington-class battlecruiser, but construction was delayed so that higher-priority anti-submarine vessels and merchant ships, needed to ensure the safe passage of personnel and materiel to Europe during Germany's U-boat campaign, could be built. After the war the ship was extensively redesigned, partially as a result of British experience. Given the hull number of CC-1, Lexington was laid down on 8 January 1921 by Fore River Shipbuilding Company of Quincy, Massachusetts.

Before the Washington Naval Conference concluded, the ship's construction was suspended in February 1922, when she was 24.2 percent complete. She was re-designated and re-authorized as an aircraft carrier on 1 July 1922. Her displacement was reduced by a total of 4,000 long tons (4,100 t), achieved mainly by the elimination of her main armament of eight 16-inch (406 mm) guns in four twin turrets (including their heavy turret mounts, their armor, and other equipment). The main armor belt was retained, but was reduced in height to save weight. The general line of the hull remained unaltered, as did the torpedo protection system, because they had already been built, and it would have been too expensive to alter them.

The ship had an overall length of 888 feet (270.7 m), a beam of 106 feet (32.3 m), and a draft of 30 feet 5 inches (9.3 m) at deep load. Lexington had a standard displacement of 36,000 long tons (36,578 t) and 43,056 long tons (43,747 t) at deep load. At that displacement, she had a metacentric height of 7.31 feet (2.2 m).

Christened by Helen Rebecca Roosevelt, the wife of the Assistant Secretary of the Navy, Theodore Douglas Robinson, Lexington was launched on 3 October 1925. She was commissioned on 14 December 1927 with Captain Albert Marshall in command. By 1942, the ship had a crew of 100 officers and 1,840 enlisted men and an aviation group totaling 141 officers and 710 enlisted men.

The ship's flight deck was 866 feet 2 inches (264 m) long and had a maximum width of 105 feet 11 inches (32.3 m). When built, her hangar "was the largest single enclosed space afloat on any ship" and had an area of 33,528 square feet (3,114.9 m²). It was 424 feet (129.2 m) long and 68 feet (20.7 m) wide. Its minimum height was 21 feet (6.4 m), and it was divided by a single fire curtain just forward of the aft aircraft elevator. Aircraft repair shops, 108 feet (32.9 m) long, were aft of the hangar, and below them was a storage space for disassembled aircraft, 128 feet (39.0 m) long. Lexington was fitted with two hydraulically powered elevators on her centerline. The forward elevator's dimensions were 30 by 60 feet (9.1 m × 18.3 m) and it had a capacity of 16,000 pounds (7,300 kg). The aft elevator had a capacity of only 6,000 pounds (2,700 kg) and measured 30 by 36 feet (9.1 m × 11.0 m). Avgas was stored in eight compartments of the torpedo protection system, and their capacity has been quoted as either 132,264 US gallons (500,670 L; 110,133 imp gal) or 163,000 US gallons (620,000 L; 136,000 imp gal).