mutuus

Mutuus is a Latin term used in ancient Roman law to denote a specific form of loan contract often rendered in English as mutuum. In a mutuum, the lender transfers a fungible thing to the borrower for consumption with the obligation to return an equivalent quantity of the same kind. Money is the most common example, though other fungible goods could be lent.

The defining feature of mutuum is that ownership of the lent item typically passes to the borrower, who must thereafter repay the same kind and amount of the item or its value. The borrower bears the risk of loss or deterioration of the borrowed fungible item and is liable for nonreturn or shortfall. The contract is generally oriented toward repayment of quantity or value rather than the return of the exact object.

Mutuum is contrasted with commodatum, a loan for use in which ownership remains with the lender and the borrower must return the precise item lent, and with depositum, where the thing is entrusted for safekeeping rather than for use or consumption. These distinctions were central to early Roman private law and helped shape later civil-law classifications of loans and deposit arrangements.

Historically, mutuum figures in classical legal writings and the Digest of Justinian as a foundational form of contract for the lending of money or fungible goods. The concept influenced the development of civil-law systems in Europe, where similar loans for consumption remain a recognized category.

Etymology: mutuus is the Latin adjective meaning mutual or reciprocal, while mutuum refers to the loan contract itself. The term has persisted in legal history to describe this specific borrowing arrangement.