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.
2. the smallest unit in the apothecaries' and avoirdupois systems, equal to 0.065 of a gram; abbreviated gr. gr The grain is obsolete as a unit in medicine, pharmacy, and nursing. Avoid the abbreviation gr, which is subject to frequent misinterpretation. Abbreviation for grain3. gr. abbreviation for grain. NR3C1