Given a class C, we may append it with the literal "group" to obtain a class of sets whose elements are instances of C, and which are related in some way.

If you're not super familiar with object oriented ontology, using the class "car" as an example, a "car group" is a set of related cars. The 2018 Toyota Camry is a car. The set of all cars designed in 2018 is a car group.

Some more examples are:

  • An operating system group. The set of UNIX-like operating systems is an operating system group.
  • A food group. The grains are a food group.

The question is: what part of speech, linguistically, is played by the word 'group'? It is not a modifier, as it cannot be removed and have the sentence remain syntactically valid. However, it also can be appended to any class and will "act on" the class in some way.

  • 1
    It's just a plain noun. It's not being appended to any class, those other words (car, OS, food, etc) are modifying it!
    – curiousdannii
    Commented Aug 22, 2018 at 5:54
  • @curiousdannii Oh haha... but then, what sort of noun is it? Certainly only very special nouns can be modified by an arbitrary class... Commented Aug 22, 2018 at 14:34
  • Its category (part of speech) is noun, and its function here is "head", i.e. head of the NP "food group". It is just a common noun, if that's what you mean.
    – BillJ
    Commented Aug 22, 2018 at 14:51

1 Answer 1


Short answer: it's a noun, plain and simple.

In certain cases, English allows a noun to modify a following noun, like an adjective would: "grocery store", "radio station", "guitar music", "laundry basket". That's what's happening here.

Note that the modifier remains a noun and not an adjective, syntactically: you can't have a *very grocery store or some *extremely guitar music.

In many cases, the two nouns end up merging together into a single one over time: department stores are fairly recent, but bookstores are older.

  • Thanks. Is there a special designation for nouns like "group", "set", or "family" though? It seems to me that these are special in the sense that any (class) noun can prepend them. You can have a "rock family", a "song family", a "lightbulb family", a "picture family", etc. (some of these phrases may seem more natural than others), but for example, you cannot have a "set store", because sets, being abstract objects, cannot be bought and sold. Commented Aug 22, 2018 at 17:01
  • @extremeaxe5 I'd say that's a semantic issue rather than a syntactic one. Syntactically, you can have a "wug shop" without knowing what a "wug" is except that it's a noun. Whether it makes any sense to buy wugs is irrelevant.
    – Draconis
    Commented Aug 22, 2018 at 17:09

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.