exponent

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

• noun One that expounds or interprets.
• noun One that speaks for, represents, or advocates.
• noun Mathematics A number or symbol, as 3 in (x + y)³, placed to the right of and above another number, symbol, or expression, denoting the power to which that number, symbol, or expression is to be raised.
• adjective Expository; explanatory.

from The Century Dictionary.

• Exemplifying; explicating.
• noun One who expounds or explains.
• noun One who or that which stands as an index or representative; one who or that which exemplifies or represents the principle or character of something: as, the leader of a party is the exponent of its principles.
• noun In algebra, a symbol placed above and at the right of another symbol (the base), to denote that the latter is to be raised to the power indicated by the former.
• noun A particular example illustrating the meaning of a general statement.

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

• noun (Alg.) A number, letter, or any quantity written on the right hand of and above another quantity, and denoting how many times the latter is repeated as a factor to produce the power indicated.
• noun One who, or that which, stands as an index or representative.
• noun one who explains, expounds, or interprets.
• noun [R.] the quotient arising when the antecedent is divided by the consequent; thus, 6 is the exponent of the ratio of 30 to 5.

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

• noun One who expounds, represents or advocates
• noun mathematics The power to which a number, symbol or expression is to be raised. For example, the 3 in x3.

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

• noun a mathematical notation indicating the number of times a quantity is multiplied by itself
• noun someone who expounds and interprets or explains
• noun a person who pleads for a cause or propounds an idea