The word "lutra" refers to a genus of animals that includes various species of otters. In simple terms, otters are playful, aquatic mammals that are often found in rivers, lakes, and oceans. They are known for their sleek bodies, webbed feet, and thick fur, which helps keep them warm in cold water.
In summary, "lutra" is a scientific term used to classify a group of otters. It is mostly used in academic or scientific discussions.