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.
In the metric system how many milligrams are in a gram? In the metric system prefix milli means 1/1000 (thousedndth) of something - in this case grams, thus there are 1000 milligrams in a gram Edit