bonus

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

• noun Something given or paid in addition to what is usual or expected.
• noun A sum of money or an equivalent given to an employee in addition to the employee's usual compensation.
• noun A sum of money in addition to salary that is given to a professional athlete for signing up with a team.
• noun A subsidy from a government to an industry.
• noun A sum of money paid by a government to a war veteran.
• noun A premium, as of stock, that is given by a corporation to another party, such as a purchaser of its securities.
• noun A sum of money that is paid by a corporation in excess of interest or royalties charged for the granting of a privilege or a loan to that corporation.
• noun Basketball An additional free throw awarded to a player who has been fouled when the opposing team has committed more than a specified number of fouls during a period of play.

from The Century Dictionary.

• noun Something of the nature of an honorarium or voluntary additional compensation for a service or advantage; a sum given or paid over and above what is required to be paid or is regularly payable.
• To give or add a bonus to; promote by the payment of bonuses.

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

• noun (Law) A premium given for a loan, or for a charter or other privilege granted to a company; as the bank paid a bonus for its charter.
• noun An extra dividend to the shareholders of a joint stock company, out of accumulated profits.
• noun Money paid in addition to a stated compensation.

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

• noun Something extra that is good.
• noun An extra sum given as a premium, e.g. to an employee.
• noun uncountable, basketball One or more free throws awarded to a team when the opposing team has accumulated enough fouls.
• verb transitive To pay a bonus, premium

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

• noun an additional payment (or other remuneration) to employees as a means of increasing output
• noun anything that tends to arouse