How do I define names for system entities?

How to best define names for the entities in my system. I have a user table. And I have a reset_password table where I relate information from the password reset process (id, hash, link_expiration_date, password_refined, new_password, is_user, status) On my system I have the template redefinir_senha_class.php I learned that names best suited for classes would be the nouns in a system specification. And is not this name "redefine_password" a noun? About this structure, any tips? Any tips on how best to define the system entities and models?