1. noun /pɹəʊˈsjuːmə/
b) A serious, enthusiastic consumer: not professional (earning money), but of similar interest and skills to a (generally lower level) professional, or aspiring to such. The target market of prosumer equipment.
2. adjective /pɹəʊˈsjuːmə/
a) A product targeted at serious, enthusiastic consumers, incorporating professional features but often modified for non-professional use.
b) A high-end consumer product more generally.
Wikipedia foundation.