Wikipedia has a pretty good entry on "Theory" in a scientific sense, but I can let you look that up if you want to see it in detail.
Regardless, for the concise verbage on it, Wikipedia Summed up a Thoery (that could be presented or some such) as a -get ready for this, this is one heck of a verbose definition-
mathematical or logical explanation, or a testable model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation.
So, if you were to try to present a scientific theory, you'd want to have some sort of mathematical model or a darn good explanation as to why something acts the way it does, to predict the way something works the way it does.
It doesn't necessarily have to be always TRUE, but it could be taken as a generalization as to why something happens, or an extremely specialized case. but as the definition brought up, there ought to be a way to (eventually) test said theory, and either prove it, or falsify it, since the scientific community is all about testing something, and reproducing results in order to prove or deny a theory or whatever. :O