Term of Art
"Term of art" is a legal term. It is so-named to set it apart from other legal terminology which, in a different context, may have a non-legal meaning. Anything said under oath in a court of law is presumably legal language. An argument may turn on a Latin word, or phrase, which is only familiar to legal professionals. What about the rest of us?
“Term of art” examples abound, too many from which to choose. Any “term of art” legal term in a news story—the one you have to search to get the point of the story—is a useful instance. A more interesting approach (for our purposes) is an inverse analogy. What, if anything, might be a “term of art” in a context other than law? -in the field of art, for instance.
By this definition a “term of art” in the field of art would be a highly contextual term possibly meaningless, or with a very different meaning, outside the field of Art. Perspective is a good example of a dual-use, both figurative and specific, "term of art." Discovered by artists, perspective is a true/false condition of art.
A painting has perspective (or not.) If it has perspective, the execution of the given perspective may be correct (or not.) Perspective is thus a lawful "term of art." Regardless of this opinion, since the Renaissance, perspective has spawned connotations far beyond the horizon of art. “Perspective” is, to give one general example, interchangeable with "point of view," just as “point of view” is derived from "vanishing point" -another true term of art.
“Perspective” can have legitimate connotations in almost any context (not limited to art.) As an informal test of my theory, I searched "use perspective in a sentence." One of the top returns included five examples, none of which had anything to do with art. That's all well and good for expository writing, but try arguing perspective in court. It would be the precise point of attack under cross-examination.
Next, I tried sentence search with “chiaroscuro,” a true technical term of art familiar to almost everybody. I gave up searching before I could find any example of a sentence using “chiaroscuro” that was not about art. The unavoidable conclusion is that “chiaroscuro” is meaningless in any context other than art, or at best, it is a writer's conceit. Chiaroscuro is thus a lawful “term of art” in Art -and only in Art.
A little advanced art historical background: Chiaroscuro is one of the Four Canonical Styles of Art. Together, they are Chiaroscuro, Sfumato, Unione, and Cangiante. There is no precise correspondence for each term in any language. And yet, even with this limitation, almost any given painting will (to the trained eye) exhibit attributes of at least one of the Four Canonical Styles of Art.
That which I am seeking to define is attributes that are at the same time artistic -but not exclusively artistic; “terms of art” that are in no context unlawful but, rather, meaningful in any context. For those predicates borrowed specifically by art and from art, there evolves an increasingly complex tangle of aesthetic denotation, meeting at the intersection of Liberal Arts, and Art. Hopefully, it opens a discussion in which specialized knowledge is not an exclusion from participating.