What is the meaning of MPa?

A megapascal (MPa) is a measure of the compressive strength of concrete. It lets inspectors know how much pressure can be applied to the concrete before it cracks or fails. One MPa is equal to one million pascals (Pa); as a pascal is one newton of force per square meter, a megapascal is one million newtons per square meter. The higher the MPa of concrete, the stronger the material will be, and the less likely it is to fail.

To simplify the above - a bag of 32.5N means that if it is mixed correctly and allowed to settle - it should reach 32 MPa in 28 days