Ruminant refers to an animal that has a specialized digestive system, specifically one with a complex stomach consisting of four chambers. These animals are able to break down and extract nutrients from plant-based foods such as grass or hay through fermentation in their stomachs. Some common examples of ruminant animals include cows, sheep, goats, deer, and buffalo. The word "ruminant" comes from the Latin term "rumen," which refers to the first chamber of a cow's stomach where fermentation begins.