Order of magnitude
WordNet
noun
(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"
(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