/ ˈθɪknəs; NAmE / noun
1.
[ U , C ] the size of sth between opposite surfaces or sides
SYN width :
Use wood of at least 12 mm thickness.
The board is available in four thicknesses.
2.
[ C ] thickness (of sth) a layer of sth :
The jacket was lined with a double thickness (= two layers) of fabric.
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WORD ORIGIN
Old English thicness (see thick , -ness ).