He is possibly the Harpocration mentioned by Julius Capitolinus (Life of Verus, 2) as the Greek tutor of Lucius Verus (2nd century AD); some authorities place him much later, on the ground that he borrowed from Athenaeus.
[1] Harpocration's Lexicon of the Ten Orators (Περὶ τῶν Λέξεων τῶν Δέκα Ῥητόρων, or briefly Λεξικὸν τῶν Δέκα Ῥητόρων), which has come down to us in an incomplete form, contains, in more or less alphabetical order, notes on well-known events and persons mentioned by the orators, and explanations of legal and commercial expressions.
The book also contains contributions to the history of Attic oratory and Greek literature generally.
[1] The Collection of Florid Expressions, a sort of anthology or chrestomathy attributed to him by the Suda, is lost, but elements of it survive in later lexica.
[1] Attribution: Greek Wikisource has original text related to this article: Αρποκρατίων