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.
Definition of gram. 1  1 : a metric unit of mass equal to 1â1000 kilogram and nearly equal to the mass of one cubic centimeter of water at its maximum density â see metric system table. 2  2 : the weight of a gram under the acceleration of gravity.