The speaker or voice of a literary work, i.e., who is doing the talking. Thus persona is the "I" of a narrative or the implied speaker of a lyric poem.
Sidelight: Sometimes the author of a poem identifies a created character as the speaker-- but in the absence of a specific attribution the term persona is applied in a neutral sense, since it should not be automatically assumed that a creative work directly reflects the personal experiences or views of the poet. The use of an identified persona precludes a potential ambiguity and enables poets to give expression to things they would prefer not to have attributed to their own person.
Sidelight: In Robert Browning's "My Last Duchess," the persona is the Duke of Ferrara. In John Keats' "Ode to a Nightingale," the persona is not identified, so it is up to the reader to infer whether it is the author himself or a speaker conceived by the poet for a particular effect.
Sidelight: The term, voice, while often used synonymously with speaker or persona, can also refer to a pervasive presence behind the fictitious voices that speak in a work, or to Aristotle's "ethos," the element in a work that creates a perception by the audience or reader of the moral qualities of the speaker or a character.
(Compare Content, Diction, Form, Motif, Style, Texture, Tone)

This definition is in context to Poetry. See more contextual defintions for Persona (Pur-soh-nuh).