The nature of an instrument, such as a check, may indicate that it is payable on demand.

Nature

The phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth, as opposed to humans or human creations.

Instrument

A formal legal document that serves as evidence of a fact or a right, and can include negotiable instruments in financial transactions.

Payable On Demand

A financial term referring to a debt or obligation that must be paid or fulfilled whenever the lender or beneficiary demands.