• A quadruped of the genus Canis, esp. the domestic dog (C. familiaris). • A mean, worthless fellow; a wretch. • A fellow; -- used humorously or contemptuously; as, a sly dog; a lazy dog. • One of the two constellations, Canis Major and Canis Minor, or the Greater Dog and the Lesser Dog. Canis Major contains the Dog Star (Sirius). • An iron for holding wood in a fireplace; a firedog; an andiron. • A grappling iron, with a claw or claws, for fastening into wood or other heavy articles, for the purpose of raising or moving them. • An iron with fangs fastening a log in a saw pit, or on the carriage of a sawmill. • A piece in machinery acting as a catch or clutch; especially, the carrier of a lathe, also, an adjustable stop to change motion, as in a machine tool. • To hunt or track like a hound; to follow insidiously or indefatigably; to chase with a dog or dogs; to worry, as if by dogs; to hound with importunity.