A more thorough explanation:

A maxim is a short and concise expression of a traditional legal principle. It is a principle that has been established over time and has become a standard in the legal system.

For example, "possession is nine-tenths of the law" is a maxim that means if someone has physical possession of something, they have a stronger legal claim to it than someone who does not. Another example is caveat emptor, which means "let the buyer beware." This maxim reminds buyers that they are responsible for checking the quality and suitability of a product before purchasing it.

Maxims are important because they provide guidance and clarity in legal matters. They are often used to support legal arguments and decisions. By using a maxim, lawyers can reference a well-established principle that has been accepted by the legal system for many years.