The phrase "because of" is commonly thought of as a preposition; by itself, "because" is also considered by some to be a subordinating conjunction. The Chicago Manual of Style doesn't capitalize any prepositions, excepting at the start of sentences. Additionally, conjunctions are not capitalized mid-line.

How would you capitalize a heading that includes "because" or "because of" according to the Chicago Manual of Style?

For example:

  • Eat because You Love Food
  • Run because of Your Future
  • 2
    If you lower-cased all phrases people have called compound prepositions, you'd have The World according to Garp, which is clearly wrong. Commented Jul 25, 2018 at 21:02
  • 2
    The capitalization rules say that subordinating conjunctions should be capitalized; you just lower-case coordinating conjunctions. And the word because is not a preposition (even if it can serve as part of a compound preposition), so it needs to be capitalized. Commented Jul 25, 2018 at 21:07
  • @WS2: the OP specifies that it's in a heading, so title case is acceptable (depending on the publisher's style preference). Commented Jul 25, 2018 at 22:52
  • @PeterShor The word because is certainly a preposition. Geoffrey Pullum gives very good arguments why it is a preposition in the second link in the question (although I’m not entirely sold on their insistence that that/what/how/etc. are the only subordinator that exist). There are also very good arguments that because of is not a compound preposition, but rather a preposition because with a PP object headed by of. Commented Jul 26, 2018 at 17:16

1 Answer 1


For reference, here is the complete list of guidelines from The Chicago Manual of Style (17th ed.), 8.159:

The conventions of headline style are governed mainly by emphasis and grammar. The following rules, though occasionally arbitrary, are intended primarily to facilitate the consistent styling of titles mentioned or cited in text and notes:

  1. Capitalize the first and last words in titles and subtitles (but see rule 7), and capitalize all other major words (nouns, pronouns, verbs, adjectives, adverbs, and some conjunctions—but see rule 4).
  2. Lowercase the articles the, a, and an.
  3. Lowercase prepositions, regardless of length, except when they are used adverbially or adjectivally (up in Look Up, down in Turn Down, on in The On Button, to in Come To, etc.) or when they compose part of a Latin expression used adjectivally or adverbially (De Facto, In Vitro, etc.).
  4. Lowercase the common coordinating conjunctions and, but, for, or, and nor.
  5. Lowercase to not only as a preposition (rule 3) but also as part of an infinitive (to Run, to Hide, etc.), and lowercase as in any grammatical function.
  6. Lowercase the part of a proper name that would be lowercased in text, such as de or von.
  7. Lowercase the second part of a species name, such as fulvescens in Acipenser fulvescens, even if it is the last word in a title or subtitle.

Let's look at eat because you love food first.

Chicago does consider because on its own to be a subordinating conjunction. Per 5.200:

A subordinating conjunction connects clauses of unequal grammatical rank. The conjunction introduces a clause that is dependent on the independent clause {follow this road until you reach the highway} {that squirrel is friendly because people feed it} {Marcus promised that he would help}. A pure subordinating conjunction has no antecedent and is not a pronoun or an adverb {take a message if someone calls}.

As it's not considered to be something that should be in lowercase, it should be in uppercase:

Eat Because You Love Food

Now, let's look at run because of your future.

Chicago doesn't discuss this specifically, so I will refer to Neal Whitman's blog post "Because as a preposition":

In Standard English, the word “because” can be used two ways. One of them is to introduce a clause, as in “Aardvark was late because he was waiting for the repairman to show up.” Used this way, “because” is a subordinating conjunction. The other is to team up with “of” to form what’s called a compound preposition. For example, “Aardvark was late because of heavy traffic.”

Let's say for the sake of argument that while because is a subordinating conjunction, because of is a preposition.

But it being a preposition isn't sufficient for it to be in lowercase.

Here, I would say that because of your future is acting as an adverbial phrase to modify the verb run.

As part of an adverbial phrase, the preposition because of seems to meet Chicago's "except when they are used adverbially" criterion in its third bullet point.

[Update: This is based on continuing feedback that I've received through comments.]

However, in a literal sense, Chicago is talking about prepositions and not prepositional phrases or compound prepositions.

At first, I had thought that there was a difference between the following sentences, and I'd based an initial conclusion on this difference.

It Came from Outer Space.
Run Because Of Your Future.

Here, I had interpreted the fact that because of was a compound preposition, each word in that compound should be treated in the same way. And, because it was acting adverbially, each word in the compound should therefore be capitalized.

Then I was presented with the following title:

Called on Account of Darkness

I questioned if on account of is exactly the same type of thing as because of.

Fowler's Dictionary of Modern English Usage says that it is:

"On account of is a slightly formal compound preposition meaning 'because of' (e.g. He remained miserable and ashamed, largely on account of his appetite which continued to torment him —A. Brookner, 1988), and first recorded in 1625.

Also, English4Dummies (a perhaps less authoritative source) lists many different compound prepositions, including because of and on account of.

To maintain consistency, all compound prepositions need to be treated in the same way—and I've never seen the headline style of on account of written as On Account Of.

Therefore, I can only conclude that Chicago is talking about prepositional words rather than prepositional phrases when it talks about adverbial and adjectival usage.

Based strictly on that, and since the single word because is acting as a preposition within because of, and not acting in an adjectival way on its own, a strict interpretations of Chicago would have the correct capitalization be:

Run because of Your Future.

Note that if I were writing the two sentences in question within the same document (or possibly even if I weren't), I would probably choose to deliberately break with this strict interpretation of Chicago because of consistency.

Eat Because You Love Food.
Run because of Your Future.

That may be a strict interpretation of Chicago, but a general audience would never appreciate the distinction. In order to maintain perceived consistency for such an audience, I would create my own style sheet with an exception for this case and instead use:

Eat Because You Love Food.
Eat Because of Your Future.

Nonetheless, after feedback and further consideration, I now believe that a strictly Chicago-based interpretation would have Because but because of.

  • 2
    Yes, the use Look Up is adverbial. But, for example, even though the prepositional phrase is acting adverbially in It Came from Outer Space, you still lower-case it because it's a preposition. For this rule, it only counts as an adverb if it's used to modify a verb and doesn't have a noun associated with it and after it. Commented Jul 25, 2018 at 21:13
  • 1
    Am I missing something? I thought this site was about English language and usage, not particularly about fine interpretation of one (of many) style guides.
    – JeremyC
    Commented Jul 25, 2018 at 21:24
  • 2
    @JeremyC Yes, that's certainly true. But asking about a specific style guide's use isn't really any different than asking about spelling that's particular to the US, for instance. Normally, answers should give alternate, and even competing, evidence for various things. But some questions can also be quite specific. I agree about your comment on "rules." I try not to use that word. (I just edited my answer to change that wording. I had used it only because I was quoting Chicago.) Commented Jul 25, 2018 at 22:00
  • 2
    I agree with Peter here. You’re misunderstanding what CMoS mean by a preposition functioning adverbially: they mean it very literally. If the preposition (not a prepositional phrase with the preposition as its head) is acting ‘adverbially’ (a somewhat hand-wavy term that in this case refers essentially to the particle in a phrasal verb), then you capitalise it. Because of is not acting ‘adverbially’ here; the whole prepositional phrase is. But prepositional phrases are essentially always ‘adverbial’, so capitalising ‘adverbial’ PPs would contradict the whole point of the rule. Commented Jul 26, 2018 at 17:02
  • 2
    Since neither because nor of (whether you see them as a compound preposition or separate prepositions in nested PPs—the CGEL evidence for the latter is compelling, in my view) is acting adverbially on their own here, they should both, according to CMoS, be lowercase. Commented Jul 26, 2018 at 17:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.