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.
Other words with the Greek root dia. 1  diagram (gram means writing): a picture that shows details such as measurement or direction or how something works. 2  dialect (lect means speech): a way of speaking thatâs specific to a location. 3  diameter ( meter means measurement): the line that passes across the middle of a circle. diaphanous (phan means show): a pretty word for see-through, as with filmy, guazy fabrics. diocese (ec/eco means house): a church district. direct (rect means right, straight): straightforward, up front.