a small cavern or hollow place in the side of a hill, or among rocks; esp., a cave used by a wild beast for shelter or concealment; as, a lion's den; a den of robbers.-a squalid place of resort; a wretched dwelling place; a haunt; as, a den of vice.-any snug or close retreat where one goes to be alone.-a narrow glen; a ravine; a dell.-to live in, or as in, a den.