People who are used to going to the gyms, after sometime they get thick skin in the palm — under each finger — because they work with their hands a lot.
What are these hard spots called in English?
When I put the word callus into my dictionary it showed me the same meaning as "warts", because we call "wart" everything on the skin that is hard, even-though there are big differences between them and the locations are different.
n.b. No specific word for it in my language, therefore I can not see the translation on a dictionary.

callusandwarthave very similar definition: "hard spot on the skin". They only differ in source: Warts are result of infection while calluses are result of physical damage. – Agent_L Nov 18 '16 at 15:01