Here are the simplified definitions of prose and poetry:
Prose--the ordinary, matter-of-fact, ordinary form of language
Poetry--the art of rhythmical composition for exciting pleasure by imaginative or elevated thoughts.
There are times when prose that contains elevated thoughts and a beauty of expression is referred to as being "poetry." Therefore, the division between the two is certainly mitigated at times by beautiful language or inspired thoughts.
While prose has as its definition, "written or spoken language in its ordinary form, without metrical structure," it certainly can share with poetry some poetic qualities such as lyricism and the use of literary devices such as metaphor, simile, symbolism, paradox, imagery, and so on.
For example F. Scott Fitzgerald, a writer of prose, is often described as a romantic lyricist because there are elements of Romanticism in his writing and the structure of his prose is so lyrical in nature at times with its balanced and poetic phrases and lilting sentence structure. Consider this passage from The Great Gatsby:
But his heart was in a constant, turbulent riot. The most grotesque and fantastic conceits haunted him in his bed at night. A universe of ineffable gaudiness spun itself out in his brain while the clock ticked on the wash-stand and the moon soaked with wet light his tangled clothes....For a while these reveries provided...a satisfactory hint of the unreality of reality, a promise that the rock of the world was founded securely on a fairy's wings. (Ch. 5)
So, while prose can often be poetic, poetry rarely is prosaic, although it can be rather mundane and matter-of-fact at times, as in some modern poems.
No poem in the traditional sense of ode, elegy, epic, sonnet, etc. can be judged as similar to prose. These formal forms have the restrictions of meter and rhyme and form. Appearance is very different as prose is composed of paragraphs and/or dialogue while poetry is arranged in verse and lines
Prose can be defined as everyday language. Prose does not adhere to metrical structure or rhyme. Instead, prose is identified as the natural flow of colloquial language. Prose comes from the Latin term “prosa oratio,” which means straightforward or direct speech. In short, prose can be described as anything that is not poetry. There are two major types of prose:
- Informal / Conversational Prose
Informal prose is inherently relaxed and familiar. It is the type of language that you might expect to hear in conversation. Informal prose can also be written. In fact, most writing follows this form of prose.
- Formal / Elevated Prose
Elevated prose, such as you might see in academic writing or creative non-fiction, is a more formal way of writing. Formal prose often uses elevated diction, imagery, or complex syntax.
In contrast to prose, poetry is a form of metrical composition that has a distinctive style and rhythm. Poetry is defined by its meter, or what we call prosody. These are the regular patterns of stressed and unstressed syllables in the poem. Some poetry is also governed by rhyme. Common types of poems include the sonnet, elegy, ballad, epic, haiku, and free verse.
Similar to formal prose, many forms of poetry rely on elevated diction, imagery, and complex syntax. However, other forms of poetry, such as the ballad, draw from the colloquial types of language you might expect from informal prose.
This is a great question. There are many similarities and differences. Let me make a list for you.
Both prose and poetry are literature that seek to express a point. They both can be artistic and require skill and lots of practice. So, from the point of view of creativity, artistry, and other literary points of view, there is much in common. So, we can say that there is very fine line between poetry and prose. What separates poetry from prose generally speaking are the followings:
First, poetry is governed by meter. For example, if you read the works of Homer it is written in the dactylic hexameter. Virgil also uses this in his Aeneid, and Lucretius in his, De Rerum Natura. There are many meters and some of them even sound like prose, which makes this very confusing, such as the works of Plautus, the Roman poet.
Second, poetry also tends to follow certain patterns, whether they be couplets, rhymes or other artistic conventions. Prose does not follow patters or better yet does not have to do so.