armadillo

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various omnivorous burrowing mammals of the family Dasypodidae, native to southern North America and Central and South America and characterized by an armorlike covering consisting of jointed bony plates.

from The Century Dictionary.

• noun An American edentate quadruped, of the order Bruta (or Edentata) and suborder Loricata, and of the extant families Tatusiidœ, Dasypodidœ, and Chlamydophoridœ, or of the extinct family Glyptodontidœ, having a hard shell or carapace like a coat of mail, resulting from a peculiar ossification of the integument and the confluence of numerous small scutes.
• noun In Crustacea: A genus of isopods, of the family Oniscidœ, including the pillbugs, which can roll themselves into a ball like the mammals called armadillos.
• noun A species of this genus; a pill-bug or sow-bug; a kind of wood-louse.
• noun A name given to an electric battery composed of copper and zinc elements riveted together, and designed to be worn as a remedy in certain diseases.

from the GNU version of the Collaborative International Dictionary of English.

• noun Any edentate animal if the family Dasypidæ, peculiar to America. The body and head are incased in an armor composed of small bony plates. The armadillos burrow in the earth, seldom going abroad except at night. When attacked, they curl up into a ball, presenting the armor on all sides. Their flesh is good food. There are several species, one of which (the peba) is found as far north as Texas. See peba, poyou, tatouay.
• noun A genus of small isopod Crustacea that can roll themselves into a ball.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of a family of burrowing mammals covered with bony, jointed, protective plates, genus Dasypus.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun burrowing chiefly nocturnal mammal with body covered with strong horny plates