| a venomous spider, Latrodectus mactans, widely distributed in the U.S., the female of which is jet-black with an hourglass-shaped red mark on the underside of its abdomen. |
| black widow n. A poisonous New World spider (Latrodectus mactans), the female of which produces extremely toxic venom and has a black shiny body with red markings. [From the fact that the female eats its mate.] |