Higher inverse order?

[terp.asessed]

What is higher inverse orders of n, as symbolized by O(n)? Please explain this to me---I am still confused even if googling it.

 

[Simon Bridge]

O(n) would be "order of n". See "big O notation".
The "order" is the power of 10. So 1000 is order 3.

An inverse order would be the negative power of 10... but I need the context.