A more thorough explanation:

A term of art is a word or phrase that has a specific meaning in a particular field or specialty, different from its general meaning in everyday language. It can also refer to jargonistic language used within a particular group or profession.

For example, in law, the phrase "and his heirs" has a specific legal meaning that is different from its everyday meaning. Similarly, "res ipsa loquitur" is a Latin term used in legal contexts to mean "the thing speaks for itself." These terms have precise meanings within the legal profession that may not be immediately clear to someone outside of that field.

Another example of a term of art is "beta testing" in the technology industry. While the word "beta" generally refers to a second version of something, in the tech industry, it specifically refers to a stage of software development where a product is tested by a select group of users before it is released to the public.

Overall, a term of art is a specialized word or phrase that has a specific meaning within a particular field or profession, and may not be immediately understood by those outside of that field.