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.
gram | grams [plural] | grammes [British, outdated, plural] | gramme [sense-specific] A unit of mass equal to one-thousandth of a kilogram. Symbol: g | A group of leguminous plants that are grown for their seeds. | [uncountable] The seeds of these plants.