What is the Black Letter Law?

Mary McMahon
Mary McMahon

Black letter law is law that is well established and generally viewed as uncontroversial. In some regions of the world, lawyers may also use this term to refer to case law that has become generally accepted. In legal discussions, when people use this term, they generally do so with the implication that the law in question is accepted and not open to argument, in contrast with other types of laws which may be more open to interpretation.

Woman holding a book
Woman holding a book

This legal term is one among many that is often given false origins. People commonly say that it is linked with a famous American text, Black's Law Dictionary, but this is not actually the case. The term “black letter law” was showing up in Supreme Court decisions nearly 50 years before this dictionary was published. The term is more probably a reference to blackletter type, a font family that was commonly used to print legal texts even after it had fallen out of favor elsewhere.

Other terms that people may use to well established law include hornbook law and trite law. “Hornbook law” is a reference to simple, basic, widely accepted law that people learn early in their legal education. In all cases, the terms are used when people are talking about laws that are generally considered quite clear and not nebulous in nature. Many of these laws come from common law, with hundreds of years of history behind them, and people without legal training are often at least vaguely familiar with them.

Since lawyers often question, challenge, and reinterpret the law as part of their work, it is important to distinguish black letter law from other types of law. Unsurprisingly, there is sometimes debate in the legal community about whether or not a law should really be considered uncontroversial. Generally, the older a law is and more frequently it has been upheld in court and in legal treatises, the more likely it is to be evaluated as generally accepted.

Changing societies call for changing laws and differing interpretations on existing legal precedent. This is critical to make a legal system function, as it cannot remain stagnant. However, black letter law often lies at the foundation of the law, and it is used in arguments to support various interpretations of the law. A lawyer might argue, for example, that a reading of related black letter law supports his or her interpretation of a particular statute.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


@ bigjim - I would be interested to know where you go to school. I go to law school at night, and we cover a fair amount of black letter law. I have heard it said that some of the more traditionally well-known or "prestigious" schools like Harvard Law or Georgetown spend a lot of time arguing the fine points of things, where schools geared more toward working adults or other nontraditional students are more into the letter of the law.

Either way, you have to know both if you want to pass the bar exam.


As a law student, I am really surprised we do not spent as much time studying black letter law as I thought we would. There just isn't as much about exactly what the law says and how the legal definition of something can be applied to help you win your cases. We spend a lot of time arguing "what if" type of scenarios.

So far, it seems that while it is important to know what the law says, it is more important to know how the courts have interpreted that law in the past, or how you can get them to interpret it in your favor in the future.

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