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 gram (g) is the standard unit of mass in the metric or System Internationale (SI) system. The gram, along with millimeters (mL), are the metric units used to measure the serving size of food and are listed on the Nutrition Facts label found on food products. Looking at the nutrition label you can see that many of the nutrients (e.g., fats, carbohydrates, and protein) are expressed in grams.