There are several synonyms for the phrase "payment for expenses," which refers to the act of reimbursing someone for costs related to a particular venture or undertaking. Some of the most common synonyms include "expense reimbursement," "cost reimbursement," "out-of-pocket reimbursement," and "expense compensation." Other similar phrases include "expense allowance," "expense stipend," "expense grant," and "cost compensation." These terms are often used in professional settings, such as when an employer is reimbursing an employee for travel expenses, but they can also be used in personal situations where one person is reimbursing another for shared expenses. Regardless of the specific context, all of these phrases refer to the same basic concept of paying someone back for money they have spent.