1.NounStock (material) suitable for making shims; often in the form of sheets of metal, plastic, or wood of various thicknesses, ready to have pieces cut out of them as needed.
"They keep 1-thou and 2-thou shimstock handy when they're building these assemblies."
2.NounMetal foil used for measurement of proposed dental work.
"They keep 8-micron and 12-micron shimstock handy when they're evaluating the occlusion."