bell metal

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

• noun An alloy of tin and copper used to make bells.

from The Century Dictionary.

• noun A variety of bronze, an alloy of copper and tin, of which bells are made.

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

• A hard alloy or bronze, consisting usually of about three parts of copper to one of tin; -- used for making bells.
• a sulphide of tin, copper, and iron; the mineral stannite.

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

• noun A hard alloy of about three parts of copper to one of tin, used for making bells.

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

• noun bronze with 3 or 4 parts copper to 1 part tin; used in making bells