I've often encountered commentators and online magazine editors advocating 'prose poetry' but I've only just found an intelligible definition of it. For this I'm beholden to Carrie Etter in her article The Sense of  Distillation: On Prose Poetry.1 Having defined poetry generally in these terms:

 A poem combines distillation (focus, concentration, etc.) and musicality. It is through the intensity that comes with focus and musicality [...] that we recognise poetry.

 she explains how she sees prose poems fulfilling this definition:

 They achieve focus by exploring a single idea or connected combination of ideas.

 which seems, however, to be mere clarification of the general definition of poetry rather than specific to prose poetry. Neither am I too sure of the universal necessity of musicality in poetry – I've read some very effective poems that are not at all musical (for example The Reckoning and The Harpy by Robert Service or the war poems of Wifred Owen). However, let's overlook these quibbles for the moment and accept these two statements as combining to form at least a partial definition of prose poetry. But she goes on to say more pertinently:

 While free verse can create rhythm through the use of line length and enjambment, prose poetry uses the sentence.

Well that's clear at least. But my immediate question is how then does prose poetry differ from well crafted prose? This too should have focus, concentration and (optionally) musicality, should explore a single idea or a group of connected ideas, and make use of sentences. It's a great pity that most modern prose doesn't, doesn't, doesn't and doesn't, being mere strings of blockbuster standard sentences off the roll, the rushed product of high pressure journalism or the inexpert output of amateur bloggers. But let's examine some carefully written alternatives.

The dream and hallucination sequences in part three of John Masefield's Sard Harker fulfil all the above requirements, for example:

 [...] he heard far up the cañon something like a voice, which was not a voice, crying in the heart of the rocks.It was a strange metallic cry of "Ohoy!" The echoes repeated it. It was no beast that he knew. It was not like a beast. It was like the voice of the rock itself.2

  as does the introductory paragraph of The Babylon Lottery 3 by Jorge Luis Borges (in Anthony Kerrigan's translation):

 Like all men in Babylon I have been a proconsul; like all, a slave; I have also known omnipotence, opprobrium, jail. Look: the index finger of my right hand is missing. Look again: through this rent in my cape you can see a ruddy tattoo on my belly. It is the second symbol, Beth. This letter, on nights of the full moon, gives me power over men whose mark is Ghimel, but it also subordinates me to those marked Aleph [...]

Are these passages prose poetry, or are they excellently crafted prose? It seems to me that, for the reader, the distinction is illusory. They've both been assumed to be prose for all the decades since they were written and they serve their purpose in powerfully expressing what the the authors intended to convey, so where do we go from here? As I see it, there's a danger of classifying on the basis of author status rather than category of the work – essentially of elevating the self as creator above the product, because the label poet has cachet over and above that of mere author. But I firmly agree with Flaubert:

 L'homme n'est rien, l'oeuvre tout!

If the work succeeds in transmitting the intended message with maximum effect to the reader, does it matter how we classify it? So if you've written a darned fine piece of prose, more power to your elbow – be proud of it. There's no need to make it sound more 'impressive' by arbitrarily calling it a poem. That could legitimately be considered mere bull.

 [1] in: Rishi Dastidar (ed.), The Craft, Nine Arches Press 2019

 [2] John Masefield, Sard Harker, William Heinemann 1924 (p. 211)

 [3] Jorge Luis Borges, Ficciones, Everyman's Library No. 166, 1993