Classification: general statements and descriptive labels

When we say a rose is a flower, we mean that a rose is an example of a class of items we call flowers; a daffodil is another example; a daisy is another example, and so on. We use a/an in this way when we wish to classifypeople, animals or things. We can classify them in two ways:

1 By means of general statements:An architectis a person who designs buildings. A clever politiciannever promises too much.

2 By means of labels(a/an + noun after the verb be): Andrew Bright is an architect

3.9.2 Classification by means of general statements
General statements with a/an often take the form of definitions:

A catis a domestic animal. Definitions of this kind are possible because we can easily think of one cat at a time. If we make general statements with cats, we are referring to the whole species, not one example, but the-meaning is the same [> 3.19.1, 3.26.1]:

Cats are domestic animals. Many uncountable nouns can be used after a/an when we are referring to 'an example of that class' [> 2.16.3]:

This is a very good coffeeIs it Brazilian?

3.9.3 Classification by means of descriptive labels[compare > 3.19.1]
We often wish to classify people in terms of the work they do, where
they come from, etc. In English (unlike many other European
languages) we need to use a/an when we are, as it were, attaching
labels to people with regard to: e.g.

The indefinite article: 'a/an'

Origins:He's a Frenchman/an American.[> App 49]

Occupation: She's a doctor/He's an electrician.Religion: She's a Catholic/He's an AnglicanPolitics: He's a Socialist/a Republican

The plurals would be: They're Frenchmen/doctors, etc. Adjectival equivalents (where they exist) can be used in place of nouns for all the above examples except occupation:

He's European/French/Catholic/SocialistBut:

What does he do¹? - He's a taxi-driver

We need a/an with any kind of 'labelling': e.g.

- with nouns: You're an angel/a saint/a wonder

- with adjective + noun: You're a good girl/a real angel

Things, animals, etc. can also be classified with a/an:
Objects: It's a (kind of/sort of/type of) bottle-opener
Insects: It's a (kind of/sort of/type of) beetle
Plants: It's a (kind of/sort of/type of) rose

A kind of, etc. is more specific when used with reference to things, etc. than when it is used for people: