What is Disproportionation, comproportionation?

Disproportionation is the reaction of a species with itself, one part being oxidised and the other reduced: $\ce{2Cu+ -> Cu^2+ + Cu}$. The reverse, two species of the same element giving one of intermediate oxidation number, is comproportionation: $\ce{2Fe^3+ + Fe -> 3Fe^2+}$.