Money is a generalized claim on all other assets both now and in the future.
A physical asset is tangible A financial asset is intangible. A claim is a right to obtain possession or enjoyment of something. A generalized claim is a right to obtain possession or enjoyment of something that is good at all times and in all places. It eliminates the problem of double coincidence of wants. It allows people to separate the sale of a good or service from the purchase of another good or service.