Full Idea
Realism in the theory of perception is that objects we perceive usually do exist, and retain some at least of the properties we perceive them as having.
Gist of Idea
Realism says that most perceived objects exist, and have some of their perceived properties
Source
Jonathan Dancy (Intro to Contemporary Epistemology [1985], 10.2)
Book Reference
Dancy,Jonathan: 'Introduction to Contemporary Epistemology' [Blackwell 1985], p.144
A Reaction
I don't see the bit about properties as essential. We could be realists, but totally mistaken about the nature of reality. There's just something there. Though personally I endorse primary qualities.