Countable

"Apple" is a countable noun, so it makes grammatical sense to have five apples.

"Happiness" is not a countable noun. It would make no sense to have 18 happinesses.

The set of prime numbers is countable.

The trouble with "trouble" is that it's sometimes a verb, sometimes a noun, sometimes countable, sometimes not. Oh, well. Trouble troubles me little, and little troubles trouble me not at all.

In a Fréchet space, the countable intersection of open dense sets is itself dense.

The indefinite article is used before countable nouns.

It's a countable noun.

In these extracts the word abuse is used in the sense of ‘an individual piece of invective’ or ‘an abusive comment’ and is clearly a countable noun.