Rigor is something strict, severe or demanding. 1  Harsh and strict treatment in the military for cadets is an example of rigor. 2  Freezing weather and ice are examples of the rigors of winter.  Difficult and challenging academic courses are an example of academic rigor.
The suffix gram means to draw or write. This is used in telegram.
Î¼g stands for micrograms. The prefix Î¼ not a letter U but the greek letter mu, stands for one millionth. A micro gram is one one millionth of a gram, 0.000 001g.