thickness

noun

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

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

   “Guitar picks come in different thicknesses.”

   “The newest form of gold created in a lab is the thickness of two atoms, according to a new study. It’s only 0.47 nanometers thick, which is one million times thinner than a human finger nail.”

   “Whether made by a small business or a household name like Scotch, washi tape comes in countless colors, patterns and thicknesses and can be used for just as many adhesive-related projects, from decorating envelopes and empty jars to creating section dividers and adhering photos/ephemera in journals.”

3. (countable)A layer.

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

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

   “Whip the cream until it reaches a good thickness.”

5. (informal, uncountable)The property of being thick (slow to understand).
6. (countable)The minimum number of planar subgraphs which a given graph can decompose into.

verb

1. (transitive)To trim (wood) to a consistent thickness using a thickness planer.

   “Even if the parts are thicknessed by machine, check for and plane out any cup with a bench plane.”