The discussion distinguishes a proper name from pronouns, demonstratives, relatives, and other ways of forming definite reference. Several of these rely prominently on prior mention or contextual information; a proper name has identification by designation as its defining property.
FormHow it identifies
زَيْدٌ — proper nameBy the name assigned to an individual.
هُوَ — pronounThrough an antecedent or contextual cue.
هَذَا — demonstrativeThrough deixis, indication or context.
الَّذِي جَاءَ — relativeThrough a relative clause that identifies the referent.
This is not an absolute ranking of superior and inferior words. An eloquent speaker chooses the form that suits the addressee's knowledge and the rhetorical situation.