Definitions
1.nounThe absolute or relative size, extent or importance of something.
2.nounAn order of magnitude.
3.nounA number, assigned to something, such that it may be compared to others numerically
4.nounOf a vector, the norm, most commonly, the two-norm.
5.nounA logarithmic scale of brightness defined so that a difference of 5 magnitudes is a factor of 100.
6.nounA measure of the energy released by an earthquake (e.g. on the Richter scale).