Is wool a countable or uncountable noun?

"Wool" can be both countable and uncountable, depending on how it's used:

Uncountable: When referring to wool as a general material or substance, it's uncountable.

* Example: "The sweater is made of wool."

Countable: When referring to individual pieces or quantities of wool, it becomes countable.

* Example: "There are five wools in the basket." (This could be referring to different types of wool, like merino wool, cashmere wool, etc.)

In general: You'll most often see "wool" used as an uncountable noun.