Final answer:
The poem "On First Looking Into Chapman's Homer" is a sonnet, which is a fourteen-line poetic form with a specific structure and rhyme scheme.
Step-by-step explanation:
The poem "On First Looking Into Chapman's Homer" by John Keats is in the form of a sonnet. A sonnet is a poetic form consisting of fourteen lines, often written in iambic pentameter, with a specific rhyme scheme and a volta, or turn in thought. There are different types of sonnets, such as the Shakespearian and Petrarchan sonnets, each with their own structures and rhyme schemes. Contrary to the formal structure of a sonnet, a haiku is a short three-line poem with a 5-7-5 syllable count, usually unrhymed and focusing on nature. A villanelle is a 19-line poem with a distinctive pattern of repeating lines and rhyme, while an epic is a lengthy narrative poem, usually recounting heroic deeds or historical events.