I am confused about the usage of the word "type". Take the following for example:

  1. A maine coon is a type of cat.

which most people believe is correct standard English. But, dictionary definitions define "type" as a group with similar qualities. So, a "type" is really plural, not singular. This seems to make sentence 1 wrong, with "a maine coon" being singular. It seems that the correct version of sentence 1 would be:

  1. A maine coon is a member of a type of cat.

What do native speakers think? Is sentence 1 correct after all because it is idiomatic , and is sentence 2 unnatural?

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    In favor of reopening: This question is nearly impossible for a non-native to answer with a dictionary. It relates to subtle knowledge about the difference between "type" and "class" that most native speakers only hold subconsciously. Many dictionaries misleadingly define a type as a "group" or "category", saying nothing about why it's weird to speak of "a member of a type" but natural to speak of "a member of a class". – Ben Kovitz Oct 10 '15 at 2:36

Meatie, I think your guess here is exactly right, and it's an excellent observation. I had never noticed it until you pointed it out. Even though "type", "kind", "class", "category", and "set" are all synonyms, it is indeed unnatural to speak of "a member of" a type or kind. The idea of membership or belonging makes sense with class, category, and set, but not type or kind.


Etymology explains the difference in thinking that makes type incompatible with member. Echoes of old usages of these words, preserved in contemporary stock phrases and compound words, still color the way we understand them. Since Ancient Greek, type (in various forms) has primarily meant striking an object to produce an impression or image, the object struck, or the image produced. For example, printing presses used movable type until the 20th century, and people typed letters on typewriters. Since the same block of metal produces a nearly identical image each time it is struck, it's natural to extend type to mean the image considered abstractly, or indeed anything considered abstractly, like a type of animal or a personality type. The metaphor is that each animal of the same type is like another image struck from the same block.

This leads you to think of the abstraction as existing separately from all its instances, like Ideas in Plato's philosophy, or like a model that copies are made from. You can see this way of thinking in the words prototype, meaning a single model of something to be manufactured in large quantity when the design is perfected; archetype, meaning the ideal form of something that recurs in many different forms; and stereotype, meaning a simplistic mental image of a class of people. These and many common usages of the word "type" tend to make people think of an abstraction as a sort of image or model when they hear or say the word "type".


The word member comes from the Latin word for a limb—that is, a part of the body, like an arm or a leg. It retains this meaning in English, and in general people think of members as parts of a larger whole. The relationship of part to whole does not make sense with the metaphor of a model or block of type from which images are struck or copied. That is why we don't normally speak of a "member of a type".

How to say it

Usually, people say that an individual is of a type, or they use the possessive case, like this:

This cat is of the Maine Coon type.

This cat's type is Maine Coon.

If you really want a noun, you can use instance, which does not suggest a part-whole relationship. It sounds a little clumsy, but this usage is common in software engineering:

This cat is an instance of the Maine Coon type.

The determiner (an article like the, a, or an, or an adjective like this or that) indicates whether the name of the type refers to the type or to a particular instance. Note that omitting a determiner is itself a determiner, and means that you are referring to the type, not to an instance:

Maine Coon is a type of cat.

The Maine Coon is a type of cat.

A Maine Coon is a type of cat. [Usually wrong, because a introduces an instance. This does occur, however, in definitions, where people supply an article (or lack of an article) to indicate the common usage. Ask a separate question about that and I'll explain more.]

This cat is a Maine Coon. [Correct: it means "This cat is an instance of the Maine Coon type."]

Modern pressures to abandon the metaphor

The above describes ordinary, lay usage. In computer science, the words class and type have specialized meanings. The word type denotes a set for which some proposition is known to be true of all its members, and the word class denotes a data structure and some program code that is associated with it. For example, "nonnegative integer" is a type; it is known that every nonnegative integer can be added to a number, and that every nonnegative integer is greater than or equal to zero. An important question is whether the proposition known to be true of a type cannot be satisfied, meaning that the set is empty—has no members. If so, this suggests that the program that defines this type contains an error.

This peculiar set of meanings has created a strong pressure to abandon the metaphor of the "model or ideal from which copies are made", and speak of "members" of types. You'll find it especially common in the field called "type theory".

Similarly, in philosophy and mathematics, people often want to use the word type in a specialized way, to denote a kind of set. So, you'll occasionally see member combined with type in those fields, too. As usual, there is no precise rule governing all usage of the word type. As with all words, people extend and vary old and familiar usages to communicate what they want to say now.

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    Sorry, could you please clarify: "A Maine Coon is a type of cat." is wrong because of the first a? Or because of the second a? – CowperKettle Dec 29 '15 at 18:37
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    @CopperKettle It's hard to explain both briefly and accurately. My first thought is that rather than blaming one a or the other, the problem with the sentence is that it half-fits two common phrasings: "A Maine Coon is a cat" and "The Maine Coon is a type of cat." And actually, if someone asks you "What's a Maine Coon?", a correct and grammatical answer is "A Maine Coon is a type of cat" (because you're echoing the phrase from the preceding sentence). – Ben Kovitz Dec 29 '15 at 21:37
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    If one wants to be really pedantic -- Maine Coon is a breed, not a type. – Sasha Dec 29 '15 at 22:02
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    @GoDucks Did you see my comment above? As usual with English, there's some context where the construct sounds natural even if out of context it doesn't. For this questioner, I figure it's most helpful to focus on the most "central", ordinary usage. I'd be delighted if you could suggest a way to cover the ability for "a Maine Coon" to stretch beyond its most ordinary usage without drowning the main idea with exceptions and corner cases. On the other hand, did you intend your comment to suggest an improvement? Usually if you have a competing answer, the best way to suggest it is to post it. – Ben Kovitz Jan 20 '16 at 22:59
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    The original poster's attempted usage is similar to 'A Maine coon cat is an instance of the type "Maine coon cat", which is a subtype of the type "cat".' That last sentence is an example of computer programming jargon, rather than ordinary English. – Jasper Jan 21 '16 at 0:30

I am confused about the usage of the word "type". Take the following for example:

  1. A maine coon is a type of cat.

which most people believe is correct standard English. But, dictionary definitions define "type" as a group with similar qualities. So, a "type" is really plural, not singular. This seems to make sentence 1 wrong, with "a maine coon" being singular. It seems that the correct version of sentence 1 would be:

  1. A maine coon is a member of a type of cat.

What do native speakers think? Is sentence 1 correct after all because it is idiomatic , and is sentence 2 unnatural?

Short Answer: Sentence 1 is correct, standard and idiomatic English. Sentence 2 is most unnatural.

Sentence 1 is so correct, standard and idiomatic that a sentence using its exact structure begins the description of the titular subject of the 2015 children's reader Life Story of a Salamander, published by the educational publisher Capstone.

enter image description here


And type is not "really plural," it is singular. Its plural is types. What appears to be throwing you off is the word group, which is notionally plural. Many dictionaries do not use the word group when defining type; instead they use such words as category, kind, sort, which—like type—are singular in number.

You say

"dictionary definitions define "type" as a group with similar qualities" (my emphasis)

This is true of definitions found in some dictionaries. For instance, Cambridge Dictionary proffers such a definition when it defines type as

a ​particular ​group of ​people or things that ​share ​similar ​characteristics and ​form a ​smaller ​division of a ​larger set (Link)

and MacMillan offers the following:

a group of people or things with similar qualities or features that make them different from other groups (Link)

With these definitions in mind, it is natural that the sincere learner might be confused when coming across sentences such as

A maine coon is a type of cat


A salamander is a type of animal

TO WIT: If a type is a group and a group must be plural, how can a (which refers to one) maine coon or a salamander be plural? This almost sounds like a trick question.

It is worth noting, first, that although group is notionally plural (it refers to more than one item), it can be grammatically singular. Group is a collective noun and may take either a singular or plural noun, depending on what you mean, that is, whether you construe group as a single unit or as a disparate throng.

Next, Oxford online, noting that it is "treated as singular or plural," defines group as

A number of people or things that are located close together or are considered or classed together (my emphasis) (Link)

Note Oxford's use of classed together as part of its definition of group.

This brings us to group as a synonym for type, kind, sort, etc., and we can construct sentences similar to the originals as

A type or kind or sort or category or class or group of cat is a maine coon.


A type or kind or sort or category or class or group of animal is a salamander.

This is not the most common use of group; for instance I doubt we would often find

A maine coon is a group of cat

but it is just possible, if we use group as a synonym for type, kind, class, category, etc.

Definitions in other dictionaries avoid this source of potential confusion by not using group in their definition of type. Here are two found in the OneLook Dictionary search for type.

A category of people or things having common characteristics (Oxford)

a kind, class, or category, the constituents of which share similar characteristics (Collins)

Meanwhile, the Oxford English Dictionary gives

6a A kind, class, or order as distinguished by a particular character (OED)

The structure that you ask about is not only correct and standard and idiomatic, it is common and plentiful. Examples abound in, for instance, Google Book searches.

Note that some examples are straight from the world of linguistics:

(140) An X is a kind/type of Y

Thus a lion is a type of animal, a snake is a type of reptile, etc. (Source)

Many others, not surprisingly, are from the worlds of semantics, philosophy, cognitive science, etc that deal with definitions or representations of classes or types.

Compare: if I tell one of my grandsons that a lynx is a type of cat, he immediately knows a great deal about lynxes because he already knows a great deal about cats. (Link)

One comes from the extended usage note regarding the words sort, type, and kind that is linked to from the definition of type found in the same Cambridge dictionary with which I started this answer.

A fastener is a type of metal button which fits together to join clothes, for example a coat might have fasteners.

The list of usages is potentially endless because it is such a common usage/structure:

a sparrow is a type of bird; a wasp is a type of insect

A poodle is a type of dog in the same way that a great white is a type of shark.

an ampersand is a type of punctuation...

A meatus is a type of canal.

In fact, a gel is a type of sol in an intermediate physical phase

A lid on a glass jar is a type of screw...A see-saw is a type of lever...a screwdriver is a type of pulley...an axe is a type of wedge (Four uses in the space of eight test questions)

A so-called kegger is a type of house party at which the attendees drink beer that is pumped from a keg into plastic cups...A rave is a type of dance party that involves dancing to loud electronic music played by a DJ

“Fast chess is a type of chess game in which each side is given less time to make their moves than under the normal tournament time controls of 60 to 180 minutes per player”

In contrast, a taxis is a type of orientation in which the animal directs its body toward or away from the stimulus.

An observational study is a type of study in which individuals are observed or certain outcomes are measured and no attempt is made to affect the outcome.

Etc., ad infinitum.


"Is a type of" already implies that it belong to the type, or group, of cats. In this sentence "a type of cat" means that the maine coon is one of the many cat subspecies, so it's not plural.

I don't think the second sentence makes much sense at all. Maybe you can rewrite it as "A maine coon is a member of the cat type", but even that does not sound right to me. I would rather say "A maine coon is a member of the cat family".

To me "type" is singular, not plural.


The correct way to say it would be "The Maine Coon is a type of cat." Using "a" instead of "the" does match common usage, but it only works because any one ("a") Maine Coon is a member of the type/breed 'Maine Coon'.


If by "A Maine coon" you are referring to a breed then sentence 1 is correct and sentence 2 is incorrect. If you mean a particular representative of the species, an actual single animal, then sentence two would be correct. Consider:

A cat is a type of animal. This cat is a member of a type of animal, namely 'cats'.

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    Also a type with multiple members is still a singular type. – elc Oct 8 '15 at 21:45
  • The usage of "type" in everyday English suggests that "type" is a singular thing, not a group of things. So "a thing belongs to a type of thing" sounds weird. But "a thing belongs to a class of thing" sounds okay. I might be wrong – meatie Oct 8 '15 at 22:37
  • Well a singular type can certainly contain multiple representatives. I'm not sure where the misapprehension is but consider this. "What type of car is that?" "A Ford" And of course there are multiple Fords. Even the subject could be plural. "Those cars, what type are they?" "They are Fords" Note the type is still singular. Of course "make" would be the better word in this example, but the generic "type" can be used. – elc Mar 9 '17 at 17:27


dictionary definitions define "type" as a group with similar qualities
; Dictionaries differ by comprehensiveness (Best ones at that include <dictionary.reference.com> and <thefreedictionary.com>. (Cf googl QKNH3f.)); ≪type≫ can mean:
  1: a group.
  2: an instance of "1".

A maine coon is a type of cat.
; This is legit; the writer most likely uses the 2nd meaning.

A maine coon is a member of a type of cat.
; This is legit; the writer most likely uses the 1st.

is [≪A maine coon is a member of a type of cat.≫] unnatural?
; Definitely not in contexts where its default alternative can be very ambiguous.

Depending on context, ≪A Maine Coon is a cat.≫ can be very ambiguous. When you say it, you probably mean this:

enter image description here

But without context, the reader may think you mean this:

enter image description here

To disambiguate, you'll have to say ≪Every Maine Coon is a cat.≫.

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