"Coat thickness" refers to how thick or thin a layer of material, such as paint or varnish, is applied to a surface. It determines the amount of the material that covers the surface, which can affect its appearance and durability. Full definition
Keeping a dog inside reduces these natural temperature changes and the need for coat thickness fluctuations. (dogcare.dailypuppy.com)
2 coats of top coat might be necessary for a completely smooth touch, depending on your top coats thickness. (cosmeticsanctuary.com)
Dogs who are always kept indoors, however, are prone to smaller fluctuations in coat thickness and tend to shed fairly evenly all year. (pets.webmd.com)