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.
The words grampa, granpa, and grandpa are all informal versions of grandfather. The seldom-used plural of grampa is grampas. The possessive is grampa's.