the approximate size of something, especially a number

The country's debt this year will be of the same order of magnitude as it was last year. 今年该国的债务与去年相比在同一数量级上。

a level in a system used for measuring something in which each level is ten times larger than the one before

These processor speeds have recently increased by two orders of magnitude (= by a hundred times). 这些处理器的速度最近增加了两个指数单位（一百倍）。