Thickness

noun

1. The property of being thick (in dimension).
2. A measure of how thick (in dimension) something is.

   "The thickness of the Earth's crust varies from two to 70 kilometres."

3. A layer.

   "We upholstered the seat with three thicknesses of cloth to make it more comfortable to sit on."

4. The quality of being thick (in consistency).

   "Whip the cream until it reaches a good thickness."

5. The property of being thick (slow to understand).