As @opensdh answered in this https://stackoverflow.com/questions/65319283/how-to-understand-the-concept-of-variable issue, the definition of the variable is unclear and generally confused by the standard. Also, @languagelawyer did some efforts on clarifying it.

A variable is introduced by the declaration of a reference other than a non-static data member or of an object. The variable's name, if any, denotes the reference or object.

I think the essence of this issue is that we use the declaration with a general meaning. In other words, the declaration may refer to declaration defined in [dcl.dcl] or member-declaration in [class.mem], or parameter-declaration in [dcl.fct], or so on, as long as it is a declaration with the meaning in English.

Why don't we use the defined grammar to eliminate these ambiguous things? Although, use the wording "declaration" is a convenient way to define some rules, sometimes it could result in some ambiguities as the question discussed in the above issue. Maybe, the definition for variable could be that

A variable is first introduced by the declaration, parameter-declaration, exception-declaration, member-declaration that declares static data member, ...(some other declarations if I omitted) of a reference or of an object. The variable's name, if any, denotes the reference or object.

These italic wordings all refer to the corresponding grammar. It would be a clear(strict) definition.

Or, if the first approach looks too long, we may define what is a declaration of an object. More precisely, which declarations create objects?

@jensmaurer @opensdh @languagelawyer @jwakely