Magnitude may refer to:

Mathematics

Euclidean vector In mathematics, physics, and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) is a geometric object that has magnitude (or length) and direction. Euclidean vectors can be added and scal ...

, a quantity defined by both its magnitude and its direction *

Magnitude (mathematics) In mathematics, the magnitude or size of a mathematical object is a property which determines whether the object is larger or smaller than other objects of the same kind. More formally, an object's magnitude is the displayed result of an orderi ...

, the relative size of an object *

Norm (mathematics) In mathematics, a norm is a function (mathematics), function from a real or complex vector space to the non-negative real numbers that behaves in certain ways like the distance from the Origin (mathematics), origin: it Equivariant map, commutes w ...

, a term for the size or length of a vector *

Order of magnitude In a ratio scale based on powers of ten, the order of magnitude is a measure of the nearness of two figures. Two numbers are "within an order of magnitude" of each other if their ratio is between 1/10 and 10. In other words, the two numbers are ...

, the class of scale having a fixed value ratio to the preceding class *

Scalar (mathematics) A scalar is an element of a field which is used to define a ''vector space''. In linear algebra, real numbers or generally elements of a field are called scalars and relate to vectors in an associated vector space through the operation of scal ...

, a quantity defined only by its magnitude

Astronomy

* Absolute magnitude, the brightness of a celestial object corrected to a standard luminosity distance *

Apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

, the calibrated apparent brightness of a celestial object * Instrumental magnitude, the uncalibrated apparent magnitude of a celestial object * Limiting magnitude, the faintest apparent magnitude of a celestial body that is detectable or detected by a given instrument. *

Magnitude (astronomy) In astronomy, magnitude is a measure of the brightness of an astronomical object, object, usually in a defined passband. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus. Magnitu ...

, a measure of brightness and brightness differences used in astronomy *

Magnitude of eclipse The magnitude of eclipse is the fraction of the angular diameter of a celestial body being eclipsed. This applies to all celestial eclipses. The magnitude of a partial or annular solar eclipse is always between 0.0 and 1.0, while the magnitude o ...

or geometric magnitude, the size of the eclipsed part of the Sun during a solar eclipse or the Moon during a lunar eclipse *

Photographic magnitude Photographic magnitude ( or ) is a measure of the relative brightness of a star or other astronomical object as imaged on a photographic film emulsion with a camera attached to a telescope. An object's apparent photographic magnitude depends o ...

, the brightness of a celestial object corrected for photographic sensitivity, symbol ''m_pg'' *

Visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

, the brightness of a celestial object in visible, symbol ''m_v''

Seismology

Seismic magnitude scales Seismic magnitude scales are used to describe the overall strength or "size" of an earthquake. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking (quaking) caused by an earthquake at ...

, the energy in an earthquake, measures include: **

Moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mwg, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. was defined in a 1979 paper ...

, based on seismic moment, supersedes the Richter scale **

Richter magnitude scale The Richter scale (), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and pr ...

, the energy of an earthquake, superseded by Moment scale **

Surface-wave magnitude The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This mag ...

, based on Rayleigh surface wave measurement through heat conduction *

Seismic intensity scales Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake. They are distinguished from seismic magnitude scales, which measure the magnitude or overall stren ...

, the local severity of a quake

Arts and media

* Magnitude (Community), a recurring character from the television series ''Community'' {{disambiguation