1. (noun)magnitude the property of relativesize or extent (whether large or small)
"they tried to predict the magnitude of the explosion"; "about the magnitude of a small pea"
2. (noun)order of magnitude, magnitude a number assigned to the ratio of two quantities; two quantities are of the sameorder of magnitude if one is less than 10 times as large as the other; the number of magnitudes that the quantities differ is specified to within a power of 10
3. (noun)magnitude relativeimportance "a problem of the first magnitude"