Reimbursement refers to the act of repaying someone for expenses that they have already incurred. It is typically done after a person has paid out money for something, such as medical bills or travel expenses, and then seeks compensation from another party, usually an employer or insurance company. The reimbursement amount covers the original cost of the expense, plus any additional fees that may have been incurred. In essence, it is a way to recover money that has already been spent, providing financial relief and assistance to the individual who paid out of pocket.