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 - a metric unit of weight equal to one thousandth of a kilogram. g, gm, gramme. metric weight unit, weight unit - a decimal unit of weight based on the gram. obolus - a Greek unit of weight equal to one tenth of a gram. carat - a unit of weight for precious stones = 200 mg. dag, decagram, dekagram, dkg - 10 grams.