A physical component can be hot swapped if it is possible to replace the element with a physically different but equivalent ...

A physical component can be hot swapped if it is possible to replace the element with a physically different but equivalent one while the containing package has power applied to it (i.e., is 'on').  For example, a fan component may be designed to be hot swapped. All components that can be hot swapped are inherently removable and replaceable .