1.
If you talk about the ~ of something, you are talking about its great size, scale, or importance.
An operation of this ~ is going to be difficult...
N-UNCOUNT: usu with supp
2.
You can use order of ~ when you are giving an approximate idea of the amount or importance of something.
America and Russia do not face a problem of the same order of ~ as Japan.
= scale
PHRASE: order inflects