No matter what you call them...
Callus, calluses, callous, callouses, callosity, callosities, corns, clavus, clavi
...we've all had to deal with them in one form or another.
Let Callous.com be your guide to info and resources about them!

Wikipedia info about a callus / callous
Google results on Foot Care
Google results on Hand Care
Google results on callus removal / callous removal
Google results on callus treatment / callous treatment