Your argument is persuasive, but I think it at least relies on a Common Law system and the jurisprudence of the English legal system and its descendants. In tha

Your argument is persuasive, but I think it at least relies on a Common Law system and the jurisprudence of the English legal system and its descendants. In that context I would be inclined to agree. All the same the term "constitution" was in use in the UK sense by the 17th century, though one may argue that your narrower definition can be traced to Roman and Classical Greek constitutions at least.