gratuity

1. Something (usually money) given in exchange for influence or as an inducement to dishonesty.
2. That which seduces; seduction; allurement.

1. (feudal law) A right to the use of a superior's land, as a stipend for services to be performed; also, the land so held; a fief.
2. An inheritable estate in land held of a feudal lord on condition of the performing of certain services.
3. An estate of inheritance in land, either absolute and without limitation to any particular class of heirs (fee simple) or limited to a particular class of heirs (fee tail).
4. Property; owndom; estate.
5. Money paid or bestowed; payment; emolument.
6. A prize or reward. Only used in the set phrase "A finder's fee" in Modern English.
7. A monetary payment charged for professional services.

noun

An additional payment given freely as thanks for service.