please define the expression NMsquared

Newton-meters squared? That doesn't sound like anything that I recognize.

A Newton is a measure of force. A Meter is a measure of length or distance. A Newton-Meter is a measure of work or torque.

Newton metre - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Newton_metre)

If you square it, you simply multiply it by itself. If it's Newton\,Meter^2

Then you only square the meter value.