Hyperkeratosis is based on the Ancient Greek morphemes hyper- + kerato- + -osis, meaning ‘the condition of too much keratin’.
It is the thickening of the stratum corneum, as a result of inflammation, as a protective response to pressure, or as a result of a genetic condition.
Some of the types of hyperkeratosis that a nail professional encounters usually are:
-calluses
-corns
-eczema
-warts
-psoriasis
English 
Portuguese 
Spanish