The mouthfeel of the coffee. Often referring to the texture or heaviness of the coffee liquid in your mouth. The amount a coffee bean roasts is a huge factor in determining this characteristic. Body typically increases as a coffee bean is roasted. And, peaks somewhere near the second crack of the coffee bean as it is roasting. Once second crack is achieved, a coffee bean is typically considered a dark roast and the body typically begins to decrease.
Body is one of the six typical characteristics that are used to measure the quality of coffee. The other five being acidity, bitterness, sweetness, aroma, and finish.