A task force (TF) is a unit or formation established to work on a single defined task or activity. Originally introduced by the United States Navy, the term has now caught on for general usage and is a standard part of NATO terminology. Many non-military organizations now create "task forces" or task groups for temporary activities that might have once been performed by ad hoc committees.
The concept of a naval task force is as old as navies, and prior to that time the assembly of ships for naval operations was referred to as fleets, divisions, or on the smaller scale, squadrons, and flotillas.
Before World War II ships were collected into divisions derived from the Royal Navy's "division" of the line of battle in which one squadron usually remained under the direct command of the Admiral of the Fleet, one squadron was commanded by a Vice Admiral, and one by a Rear Admiral, each of the three squadrons flying different coloured flags, hence the terms flagship and flag officer. The flag of the Fleet Admiral's squadron was red, the Vice Admiral's was white and the Rear Admiral's blue. (The names "Vice" (possibly from advanced) and "Rear" might have derived from sailing positions within the line at the moment of engagement.) In the late 19th century ships were collected in numbered squadrons, which were assigned to named (such as the Asiatic Fleet) and later numbered fleets.