The speaker is the imaginary voice assumed by the writer of a poem. In many poems, the speaker is not identified by name. The speaker may be a person, an animal, a thing, or an abstraction.
the narrator of a poem. Note that the speaker of a poem is not the same thing as the poet. The speaker is a voice created by the poet to narrate the poem.
the narrator of a story or poem
the "persona" of the poem; whoever is speaking as the voice of the poem (which is often not the poet!)
The voice in a poem. The speaker may be the poet or a character created by the poet. The speaker may also be a thing or an animal.
the person, not necessarily the author, who is the voice of a poem.
personage or persona responsible for the voice in a poem; like the persona, the speaker should not be confused with the poet. Example: Huck Finn is the speaker in Huckleberry Finn.