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. Vectors can be added to other vectors ac ...

, 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 order th ...

, the relative size of an object *

Norm (mathematics) In mathematics, a norm is a 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: it commutes with scaling, obeys a form of the triangle inequality, and is ze ...

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

Order of magnitude An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic dis ...

, 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 scala ...

, a quantity defined only by its magnitude

Astronomy

Absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

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

Apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

, the calibrated apparent brightness of a celestial object *

Instrumental magnitude Instrumental magnitude refers to an uncalibrated apparent magnitude, and, like its counterpart, it refers to the brightness of an astronomical object seen from an observer on Earth, but unlike its counterpart, it is only useful in relative compariso ...

, the uncalibrated apparent magnitude of a celestial object *

Magnitude (astronomy) In astronomy, magnitude is a unitless measure of the brightness Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the lumi ...

, 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 ...

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, the brightness of a celestial object corrected for photographic sensitivity, symbol ''m_pg'' * Visual magnitude, the brightness of a celestial object in visible, symbol ''m_v''

Seismology

* Seismic magnitude scales, the energy in an earthquake, measures include: **

Moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, 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. It was defined in a 1979 pape ...

, 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 Francis Richter and presented in his landmark 1935 ...

, 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 ma ...

, based on Rayleigh surface wave measurement through heat conduction * Seismic intensity scales, the local severity of a quake

Arts and media

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