The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
order of magnitude
NOUN:
Inflected forms: pl. orders of magnitude 1. An estimate of size or magnitude expressed as a power of ten: Earth's mass is of the order of magnitude of 1022 tons; that of the sun is 1027 tons.2. A range of values between a designated lower value and an upper value ten times as large: The masses of Earth and the sun differ by five orders of magnitude.
