A more thorough explanation:

and

Conjunction. This small word is important in law because it determines whether one or both owners have to sign documents.

• If a car registration says "Barney and Sarah Oldfield," then both Barney and Sarah must sign off on the sale of the car.
• If a car registration says "Barney or Sarah Oldfield," then only one of them needs to sign off on the sale of the car.
• If Barney dies and the car registration says "Barney or Sarah Oldfield," then the car will automatically be in Sarah's name. However, if the registration says "Barney and Sarah Oldfield," then the car will not automatically be in Sarah's name.

These examples illustrate how the word "and" or "or" can have a big impact on legal documents. If a document says "and," it means that both parties must be involved in any decisions or transactions related to the document. If a document says "or," it means that only one party needs to be involved.