Source : WordNet®

order of magnitude
     n 1: a degree in a continuum of size or quantity; "it was on the
          order of a mile"; "an explosion of a low order of
          magnitude" [syn: {order}]
     2: a number assigned to the ratio of two quantities; two
        quantities are of the same order 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 [syn: {magnitude}]