I am editing my brother’s paper, and I realized I am unsure about the possessive form of Marine Corps, such as

The best kept secret of the Marine Corps

Is it

the Marine Corps’ best kept secret


the Marine Corp’s best kept secret

I am leaning towards the first because the s is part of the word corps.

  • 1
    The US Marine Corps is not plural. There can be only one. – Oldcat Jun 25 '14 at 0:10

As a Marine myself, I can tell you that "Marine Corp's" is completely wrong.

It is technically correct to use either:

Marine Corps's
Marine Corps'

If you look hard enough you will find examples of both, and typically one may be preferred. I have never seen either stated as incorrect; one is either more or less preferred than then other.

I personally would stay away from using "Marine Corps's" not only because of personal preference, but because you will get the occasional mispronunciation as "corpses", which, while it is often a Marine's primary mission to turn an enemy into a corpse, we do not like to hear our name mispronounced as such.

  • Thank you for answering. I do not mean to disrespect your service in any way, and I respect your experience with seeing both spellings written in formal documents relating to your Corps. But I believe that if you spell it Marine Corps’ without an s at the end, then it must be pronounced the same as Marine Corps itself is, since that apostrophe is mere punctuation, not a letter that can carry sound. That leads to creating a homophone with core rather than one with cores, which is how the possessive is said. Adding an apostrophe does not “unsilence” a silent-s. Just ask Camus. :) – tchrist Jun 25 '14 at 3:49
  • While the omission of the added 's' does sometimes result in that 's' not being pronounced, that does not necessarily hold true all of the time. Since they are both technically correct it is still a matter of preference to both the writer and the reader. We are then left with possibilities that Corps'/Corps's can be mispronounced as either 'core' or 'corpses' (I have indeed heard both); I believe the former is most preferable. – KnightHawk Jun 25 '14 at 12:42

There is a Marine Corps writing guide [here]. 1 It is not clear on the specific question you ask, but it does not use Marine Corps'. Marine Corp's is out of the question.


Great question!

Technically, the word corps is singular. You could therefore make an argument for the use of the regular possessive form: the Marine Corps’s secret.

Things are complicated by the fact that Marine Corps is also a proper name. Once again, we expect the regular possessive form, except in the case of commonly accepted usages like Jesus’ suffering and Achilles’ heel.

I suspect many authors treat corps as plural. Consequently, the shortened form the Marine Corps’ secret is likely prevalent.

My personal bias is for accepted usage. Others on this forum may prefer the more logical “prescriptive” answer. As is often the case in such gray areas, when there is no “right” there is “consistent.”

Incidentally, it is possible to find both forms in well-regarded papers like The New York Times. Consider the following two examples:

This was one sequence in the Combat Endurance Test, the opening exercise in the Marine Corps’ Infantry Officer Course — one of the most redoubtable male-only domains in the American military.1


Like the men, women will have to perform the exercises on the Marine Corps’s annual physical fitness test as “dead hang” pull-ups, without the benefit of the momentum from a lower-body swing.2

  1. http://web.archive.org/web/20140129050256/http://www.nytimes.com/2012/07/09/us/grueling-course-for-marine-officers-will-open-its-doors-to-women.html?pagewanted=all
  2. http://web.archive.org/web/20140625034125/http://www.nytimes.com/2013/02/02/us/politics/first-pull-ups-then-combat-marines-say.html?module=Search&mabReward=relbias%3As%2C[%22RI%3A5%22%2C%22RI%3A16%22]
  • Yes, the simplest answer is best, and is the one used by people who know what they’re doing, like The New York Times. But please pretty please, per meta.english.stackexchange.com/a/4722, please ‘never’ use 𝚖𝚘𝚗𝚘𝚜𝚙𝚊𝚌𝚎𝚍 𝚝𝚎𝚡𝚝 or ˋbackticksˋ on ELU. – tchrist Jun 25 '14 at 2:07
  • Unfortunately, people who know what they are doing do not agree. NYT uses both forms as in Marine Corps’ Infantry Officer Course, nytimes.com/2012/07/09/us/… – denten Jun 25 '14 at 3:31

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