There are a number of different defensive and offensive formation types used by fleets across the galaxy. Most corporations have an internal war diary which dictates their preferred formation types and variations on them, but by and large galactic military doctrine accepts the following names as "normal."
A defensive fleet formation designed for escorting ships or fleets. The Standard formation requires the ability to field at least fifty ships of varying types, and dictates a somewhat rigid formation. It has been in use since the early days of the Corporation War, though it sees much less frequent use anymore.
A defensive fleet formation based on the Standard formation, intended for escorting large fleets of ships. A fully stocked First-Class formation requires at least 75 ships to form, though more than 100 is usually preferred. First-Class places more emphasis on shifting movements for the ships inside the formation, and is a popular formation used with carrier groups.
Standard and First-Class defensive fleet formations employ the use of so-called skins, or a fleet of small ships that fly in a roughly spherical formation around the object of defense. Fleets may employ more than one skin, each additional skin enclosing the one below it. Double-Skinned fleets are common, while triple and even quadruple-skinned fleets are seen with exceptionally large fleets. Some corporations can field fleets capable of maintaining a quint-skinned fleet, but in addition to being ostentatious and wasteful, the fifth skin is usually so widely spread as to provide virtually no defensive benefit.
Each formation uses ships in a number of different ways, though there is a set of terms that finds common use across many different fleet formations.
In Standard and First-Class formation types, the Helmet position denotes the flagship of the fleet. This ship sits at the center of the formation closest to whatever the fleet is trying to protect.
In Standard and First-Class formation types, the Flex position falls to the first response patroller. This ship is responsible for quickly traversing the interior of the defensible area bounded by a skin. Depending on the number of skins, there may be more than one flex position ship in the fleet, and depending on the size of each skin there may be two or three flex position ships inside of each skin.
In First-Class formation types, the Turnip position falls to the vice-flagship of the fleet. This ship holds position to the rear of the main defense object, ready to move forward and assume command if the flagship is disabled or destroyed.
In Standard and First-Class formation types, the Pole position falls typically to the fastest ship in the fleet. Standard Pole position places the ship at the front of the fleet in relation to direction of travel, while First-Class places the Pole position in the rear, as a part of the innermost skin. The Pole ship is responsible mainly for pursuing any ships that attempt to break through the skin, whether they are successful or not. Even if the offending ship flees, the Pole ship will be expected to pursue and destroy them if possible.
In Standard and First-Class formation types, the Chuck position falls typically to a large cargo ship that holds position near the object of defense. The object of the Chuck position is to act as a decoy for the actual ship being defended, and there may be more than one Chuck depending on the size of the fleet. Standard formations are very strict about the placement of the Helmet very close to the object of defense, while First-Class formations encourage the Helmet to move back and forth between any Chucks present and the object of defense, in the interest of added confusion.
In Standard and First-Class formation types, the Skinners are the ships which maintain the protective skins around the core fleet. These are usually small attack ships, depending on the size of the fleet, and serve the purpose mainly of providing the Helmet with eyes and first responders at least several light-minutes away from the fleet proper. A ship trying to breach a skin will have to first engage or bypass these little buggers. Most ships die here.