I am writing a scientific paper and I wonder if 's is only used refering to a possession.

For example, I think "bird's feathers" is a correct expression, but I wonder if "bird's exposure", meaning exposure of birds to something (here I write about pollutants), it's correct or it's written "bird exposure".

In general, I guess my question is about the use of 's as "[something]'s [something]" instead of "[something] of [something]". Another example would be "feather's formation" or "feather formation" instead of "formation of feather".

I hope I have explained myself properly. Thanks!


If I understand your question (and I am not fully confident that I do), there are two basic ways to show "possession" in English.

"The man's job ..." or "the job of the man ..." are both grammatically valid. Notice, however, that the man almost certainly does not legally own his job, nor does he have his job in his jacket pocket. The grammatical notion of "possession" is broader than the concepts of legal possession or even physical possession. It extends to virtually any kind of relevant relationship.

So you can say "a bird's exposure to pollutants may lead to defective eggs" to mean "a bird exposed to pollutants may lay defective eggs."

By the way. "exposition" does not mean "exposure."

I hope this addresses your question.

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  • Oops! Sorry, I meant exposure, not exposition. In the paper I've written exposure, I promise ;) You're right, the grammatical notion of "possession" is broader, I got that. But, for example, it would be correct to write "bird exposure" or it is mandatory to use the 's and write "bird's exposure". Thank you very much for your answer, Jeff! – Espe Gil Jul 30 '18 at 13:15
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    @EspeGil What you are really asking is about the use of a noun to modify another noun (or Noun Adjunct) English speakers do this all the time. Bird exposure is a typical example. Whether it's correct is a matter of context and idiomatic use rather than grammar. english.stackexchange.com/questions/218157/… – Ronald Sole Jul 30 '18 at 13:41

The Cambridge Grammar of the English Language by Huddleston, Pullum, et al. (2002) lists six types of genitive ('s) construction, outlining them on p.467. They are: subject-determiner, subject of gerund-participial, fused subject-determiner-head, oblique genitive, predicative genitive, attributive genitive (with two subtypes, descriptive and measure genitives). Descriptive genitives include a glorious summer's day, a ship's doctor, fisherman's cottages, and none of these denotes possession.

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"X's Y" and "Y of X" have basically the same meaning, they just sound different in different sentences, as others have pointed out in their discussions of the proper uses of the genitive. I'd like to discuss the other form you're using.

The form "X Y", in your example "bird exposure", is NOT forming a possessive. What this does is it creates a compound noun, with the more essential part of the noun coming last (head-final), and the other nouns modifying the final noun.

For example, consider "passenger train" and "freight train". If you were to describe either simply, you would say that it's a train. What's the difference, then? One is a train that carries passengers, the other is a train that carries freight.

Contrast this to "passenger's train". This is still a train, but the train itself has no description except that this passenger "possesses" it in the various ways that the genitive might usually imply. Who is the passenger, though? You might make a construction like this if you were a taxi driver, and someone paid you to take them to the train station.

There was construction on the road, so we didn't make it in time for my passenger's train.

Relating back to your question, the construction "bird exposure" describes a type of exposure. Specifically, an exposure to birds or relating to birds. This kind of sounds like you're describing some adverse effect one might get from being near birds. Taking advantage of this construction to form a relevant sentence, you could try something like:

The pollutant exposure has caused the birds...

Similarly, "feather's formation" would refer to the formation of a feather, while "feather formation" would be a formation made out of feathers, or something similar.

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