An octopus ( or ; plural: octopuses, octopi, or octopodes; see below) is a cephalopod mollusc of the order Octopoda. It has two eyes and four pairs of arms and, like other cephalopods, it is bilaterally symmetric. An octopus has a beak, with its mouth at the center point of the arms. An octopus has no internal or external skeleton (although some species have a vestigial remnant of a shell inside their mantles), allowing it to squeeze through tight places. Octopuses are among the most intelligent and behaviorally diverse of all invertebrates.

An octopus is a sea animal with eight limbs.