Hard rubber

Rubber Rub"ber, n. 1. One who, or that which, rubs. Specifically: (a) An instrument or thing used in rubbing, polishing, or cleaning. (b) A coarse file, or the rough part of a file. (c) A whetstone; a rubstone. (d) An eraser, usually made of caoutchouc or a synthetic rubber[4]. (e) The cushion of an electrical machine. (f) One who performs massage, especially in a Turkish bath. (g) Something that chafes or annoys; hence, something that grates on the feelings; a sarcasm; a rub. --Thackeray. [1913 Webster]

2. In some games, as bridge or whist, the odd game, as the third or the fifth, which decides the winner when there is a tie between the players; as, to play the rubber; also, a contest determined by the winning of two out of three games; as, to play a rubber of whist. --Beaconsfield. ``A rubber of cribbage.'' --Dickens. [1913 Webster]

3. India rubber; caoutchouc; gum elastic; -- also called {natural rubber}. [1913 Webster +PJC]

4. Any substance, whether natural or synthetic, resembling India rubber with respect to its elasticity[1]. [PJC]

5. A low-cut overshoe made of natural or synthetic rubber[4], serving to keep the feet and shoes dry when walking in the rain or on a wet surface; -- usually used in the plural. [1913 Webster]

6. A {condom}. [Slang] [PJC]

{Antimony rubber}, an elastic durable variety of vulcanized caoutchouc of a red color. It contains antimony sulphide as an important constituent.

{Hard rubber}, a kind of vulcanized caoutchouc which nearly resembles horn in texture, rigidity, etc.

{India rubber}, caoutchouc. See {Caoutchouc}.

{Rubber cloth}, cloth covered with caoutchouc for excluding water or moisture.

{Rubber dam} (Dentistry), a shield of thin sheet rubber clasped around a tooth to exclude saliva from the tooth. [1913 Webster]