Shooting target in the context of Cowboy action shooting

In geometry, two or more objects are said to be concentric when they share the same center. Any pair of (possibly unalike) objects with well-defined centers can be concentric, including circles, spheres, regular polygons, regular polyhedra, parallelograms, cones, conic sections, and quadrics.

Geometric objects are coaxial if they share the same axis (line of symmetry). Geometric objects with a well-defined axis include circles (any line through the center), spheres, cylinders, conic sections, and surfaces of revolution.

Shooting sports are a group of competitive and recreational sporting activities which focus on shooting accuracy, precision and speed. Shooting is the art of using ranged weapons, mainly firearms and airguns, such as handguns, rifles and shotguns, and also bows/crossbows.

Shooting sports can be categorized by equipment, shooting distance, targets, time limits and the degree of athleticism involved. Shooting sports may involve both team and individual competitions, and team performance is usually assessed by summing the scores of the individual team members. Due to the noise and high impact energy of the projectiles, which can be lethal, shooting sports are typically conducted at either designated permanent shooting ranges or temporary shooting fields in areas away from human settlements.

The bullseye or bull's eye has, since 1833, been the name for the center of a target and, by extension, since 1857, has been given to any throw, toss, or shot that hits the center.

A milliradian (SI-symbol mrad, sometimes also abbreviated mil or mils) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of firearm sights by adjusting the angle of the sight compared to the barrel (up, down, left, or right). Milliradians are also used for comparing shot groupings, or to compare the difficulty of hitting different sized shooting targets at different distances. When using a scope with both mrad adjustment and a reticle with mrad markings (called an "mrad/mrad scope"), the shooter can use the reticle as a ruler to count the number of mrads a shot was off-target, which directly translates to the sight adjustment needed to hit the target with a follow-up shot. Optics with mrad markings in the reticle can also be used to make a range estimation of a known size target, or vice versa, to determine a target size if the distance is known, a practice called "milling".

Milliradians are generally used for very small angles, which allows for very accurate mathematical approximations to more easily calculate with direct proportions, back and forth between the angular separation observed in an optic, linear subtension on target, and range. In such applications it is useful to use a unit for target size that is a thousandth of the unit for range, for instance by using the metric units millimeters for target size and meters for range. This coincides with the definition of the milliradian where the arc length is defined as ⁠1/1,000⁠ of the radius. A common adjustment value in firearm sights is 1 cm at 100 meters which equals ⁠10 mm/100 m⁠ = ⁠1/10⁠ mrad.

Darts is a competitive sport in which two or more players bare-handedly throw small sharp-pointed projectiles known as darts at a round target known as a dartboard.

Points can be scored by hitting specific marked areas of the board, though unlike in sports such as archery, these areas are distributed all across the board and do not follow a principle of points increasing toward the board's bullseye. Though a number of similar games using various boards and rules exist, the term "darts" usually now refers to a standardised game involving a specific board design and set of rules.