You will be given a definition of a task first, then some input of the task.
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

A tip ( also called a gratuity ) is an amount of money given as gratitude to somebody who has provided a service .
Output:
A gratuity ( also called a tip ) is a sum of money customarily given by a client or customer to certain service sector workers for the service they have performed , in addition to the basic price of the service .