definition of
order of magnitude

[1] #1 order of magnitude n. 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". wn

[2] #2 order of magnitude n. 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. wn