- The third letter of the Greek alphabet. See Table at alphabet. (noun)
- The third item in a series or system of classification. (noun)
- A unit of magnetic intensity equal to one hundred thousandth (10-5) of an oersted. (noun)
- A unit of mass equal to one millionth (10-6) of a gram. (noun)
- Chemistry The third position from a designated carbon atom in an organic molecule at which an atom or a radical may be substituted. (noun)
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.