Описание тега template-specialization
Template specialization refers to programmer-generated explicit specialization of templates for specific types.
Templates refer to the ability to write code that works for any type satisfying the operations used within the class and/or function on that type. Template specialization refers to the ability for the programmer to explicitly change the code for a given type, either by a partial specializion of the template (in which a subset of parameters are specialized over), or a full specialization of the template (where all parameters are specialized).