Definition of "twin" []

• One of two offspring born at the same birth. (noun)
• One of two identical or similar people, animals, or things; a counterpart. (noun)
• Mineralogy Two interwoven crystals that are mirror images of each other. (noun)
• A twin-size bed. (noun)
• Being two or one of two offspring born at the same birth: twin sisters. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "If one twin is autistic, it's twelve times more likely than the average rate that the other twin is autistic."
• "In fact, not only does the US government run an internal account deficit (1), or CAD, but the twin is at 700 billion USD a year!"
• "LIN: For our viewers who are just tuning in right now, you are looking at live picture of the World Trade Center tower, where, according to eyewitness Sean Murtagh -- he is the vice president of finance and eyewitness to what he describes as a twin-engine plane -- or possibly a 737 passenger jet -- flying into the World Trade Center."