Can you be more specific? Do you mean " He has a fear of heights"?

Nouns can be countable or uncountable. Countable nouns can be counted, e.g. an apple, two apples, three apples, etc. Uncountable nouns cannot be counted, e.g. air, rice, water, etc. When you learn a new noun, you should check if it is countable or uncountable and note how it is used in a sentence.

It means that some nouns can be counted: I want a coffee, we want two coffees. And these nouns can also be used in a general sense. A lot of coffee is grown in Brazil.