conformance targets not well-defined

The conformance targets or possible implementations that are subject to conformance are not well defined: we read "Implementations and specifications " in the conformance clause. These need be defined even if only intuitively. What is the difference between Implementations and specifications ? Can we use another term than "specifications" which is rather overloaded (also used for "this specifications" - are we talking of different classes of specifications?). At some other place we read "an application or specification..." - needs be defined too in this context. The base specification (PIM V1.0) also uses "specifications" as conformance target, but not defined.