semordnilap
Well-known
It means it produces images almost or equal to the top of the line pro cameras but is priced so that keen amateurs or hobbyists can afford it. i.e. its good enough for both pros and consumers hence prosumer.
Just because it has a definition doesn't make it a word. 😉 Anyway I prefer the 'producer + consumer' alternate definition, even though that's not at all in use, and still makes an awful-sounding letter mush!