What is alpaca wool called?

An alpaca's wool is called a fleece or fiber because it's finer than most wool. it's the 3rd most expensive fiber in the world.

Another Answer

Alpaca wool is called Alpaca wool. Wool is a generic Word used to describe fibre spun from fleece, regardless of the type of fleece-bearning animal that produces it. Alpaca, then, used as a descriptor, modifies the Word wool and specifies the source of the fleece: thus -- Alpaca wool.