An isopod is a type of crustacean belonging to the order Isopoda. They are characterized by their segmented bodies and jointed legs, which allow them to move efficiently in various environments. Isopods can be found in marine, freshwater, and terrestrial habitats, with some species living in deep ocean waters while others thrive in soil or leaf litter. Isopods vary in size and appearance, ranging from tiny species measuring just a few millimeters to larger ones like the giant isopod, which can grow up to 30 centimeters long. They play important roles in ecosystems as decomposers, helping to break down organic matter and recycle nutrients.