order of magnitude

noun

1. the approximate size of something, esp measured in powers of 10the order of magnitude of the deficit was as expected; their estimates differ by an order of magnitude Also called: order

A rough measure of the size, or magnitude, of something, expressed as a power of ten: “The mass of the Earth is of the order of magnitude of 1024 kilograms.” Also, the range of values that such a rough statement applies to.