The idiom "应有尽有" (yīng yǒu jìn yǒu) is formed through a parallel and amplifying four-character structure common in Classical Chinese. It combines two verb phrases: "应有," meaning "ought to have" or "should have," with "尽有," meaning "to have entirely" or "to have all." The construction works by first establishing a category of things that are expected or needed ("应有") and then intensifying it to an absolute degree of completeness ("尽有"). This creates a powerful rhetorical effect of totality, meaning "to have everything that should be there" or "to lack nothing," emphasizing that all conceivable items within a given context are present.