Here's one title that includes a hyphenated words. Also this includes a word that is sometimes capitalized in title case.

Aliens are coming in the not-too-distant future!

Or an article called:

AIP-040 Non-Fungible Token Standard

Is it the responsibility of the style guide to fully specific how title case works? If so, this question is for naught.

But if title case actually has some universal meaning then how do we apply that meaning to hyphenated words?

closed as primarily opinion-based by Jason Bassford, JJJ, Phil Sweet, Edwin Ashworth, Chappo Aug 16 at 14:18

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • “Aliens are coming soon” sounds better and avoids the problem. “The Alien Invasion is imminent!” even better. Matter of taste whether to capitalize imminent. – David Aug 8 at 16:30
  • Less contrived example added – William Entriken Aug 8 at 17:05

In a title, capitalize both parts of a temporary compound, says Words Into Type, a temporary compound being words that are not normally joined by a hyphen. An example it gives: "Well-Known Authors." The words well and known are joined by a hyphen only when they form a compound modifier, so they are a temporary compound. A permanent compound would be a word that is always hyphenated. Words Into Type gives the example son-in-law and says that in a title, only the first part of the word (son) would be capitalized.

  • Can you give a reference for "Words into Type"? Even if it’s a link to buy it on Amazon? – Pam Aug 8 at 20:29

The Chicago Manual of Style's guidelines for hyphenated words in titles:

Capitalize the first element of the hyphenated word.

Capitalize subsequent elements unless they are articles, prepositions, or
coordinating conjunctions (and, but, for, or, nor): High-Quality Web Services First-Rate U.S. Lawyers Bed-and-Breakfast Options in Savannah

Capitalize the second element in a hyphenated spelled-out
number. Forty-Ninth Street Blues Do not capitalize the second element if the first element is a prefix that could not stand alone by itself (such as anti- or pre-). Anti-inflammatory Dieting

  • Words Into Type, Third Edition (Englewood Cliffs, NJ: Prentice-Hall, 1974). It's undoubtedly out of print but there must be copies available. Even the obsolete parts about typesetting are very informative, and the sections on editing and page makeup are well written with lucid examples. It also has some great lists, such as which prepositions go with which words. – Literalman Aug 9 at 17:18

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