Countable nouns can be counted individually, such as "apples" or "cars."

Uncountable nouns cannot be counted individually, such as "water" or "sand."

Some nouns can be both countable and uncountable, depending on their usage in a sentence.

Countable nouns often have plural forms, while uncountable nouns do not.

Uncountable nouns are often used with quantifiers like "some" or "a lot of" to indicate their quantity.