A more thorough explanation:

Definition: Traditio rei is a term used in Roman law to refer to the simple delivery of a piece of property from one person to another with the intention of transferring ownership. This was the easiest way to transfer ownership and was eventually applied to land as well as movable property. Constructive delivery was later developed.

Examples: If John gives his car keys to Jane and says "this car is now yours," this is an example of traditio rei. Similarly, if a farmer gives a cow to his neighbor with the intention of transferring ownership, this is also an example of traditio rei.

These examples illustrate the concept of traditio rei because in both cases, there is a simple delivery of property from one person to another with the intention of transferring ownership. The act of giving the car keys or the cow is enough to transfer ownership, without the need for a formal contract or legal document.