an award (as for meritorious service) given without claim or obligation a relatively small amount of money given for services rendered (as by a waiter)
Also known as co-op or honorarium Money given to respondents of a study Usually given when the interview is longer than a few minutes, respondents are asked to travel or take part in more than one phase of research, or respondents are business professionals
A gratuity is a large gift of money that is given to someone when they leave their job, especially when they leave the armed forces. He is taking a gratuity from the Navy