What term describes the elimination of undigested waste products?

The term that describes the elimination of undigested waste products is egestion. This process specifically involves the expulsion of materials from the digestive system that the body has not absorbed and cannot use for energy or nutrients. Egestion is a vital function in maintaining homeostasis, as it helps remove excess or non-nutritive substances from the organism's body.

Absorption refers to the process through which nutrients from digested food are taken up into the bloodstream and utilized by the body, rather than the elimination of waste. Excretion is a broader term that encompasses the removal of waste products from metabolism and other cellular processes, which can include urine and other metabolic by-products, not just undigested food. Defecation is often used interchangeably with egestion in everyday contexts, but it more specifically refers to the act of expelling feces as a whole, which includes egested materials but may not all strictly be undigested waste.

Thus, egestion is more accurately used to refer to the specific elimination of those undigested parts of food.