What does Acrylic mean?

Synthetic fibre made from a polymer by combining coal, air, water, petroleum and limestone.

Heddels explains Acrylic

Acrylic is wool-like, pills easily, lightweight, soft, and warm.  It is often used as a substitute for cashmere as it is more inexpensive and not found in raw denim.

Additional Resources

Scarves are one garment that use acrylic fibres: