Before 1864 the entire fleet of the Royal Navy was divided into three squadrons, the red, the white, and the blue.
Today, a squadron might number three to ten vessels, which might be major warships, transport ships, submarines, or small craft in a larger task force or a fleet.
In the United States Navy, the term squadron has always been used for formations of destroyers and submarines.
Most navies began to abandon the squadron as a tactical formation during the Second World War.
The need to provide capital ships with the anti-submarine protection of a destroyer screen and air cover from an aircraft carrier led to the increasing use of the carrier battle group, or ad hoc task forces, composed of whichever ships were available for a particular operation.