*facepalm*
All of science is 'just' a theory.
http://wordnetweb.princeton.edu/perl/webwn?s=scientific theory - scientific theory (a theory that explains scientific observations) "scientific theories must be falsifiable"
http://en.wikipedia.org/wiki/Scientific_theory#Science - In science, the word theory is used as a plausible general principle or body of principles offered to explain a phenomenon....... is for this instance that a scientific theory is a claim based on a body of evidence.
...a scientific theory is understood to be a testable model capable of predicting future occurrences or observations and capable of being tested through experiment or otherwise verified through empirical observation
According to the United States National Academy of Sciences,
"Some scientific explanations are so well established that no new evidence is likely to alter them. The explanation becomes a scientific theory. In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature supported by facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena, [5]
A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. The theory of biological evolution is more than "just a theory." It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease. Our understanding of gravity is still a work in progress. But the phenomenon of gravity, like evolution, is an accepted fact.[6]"
5 ^ National Academy of Sciences (2005), Science, Evolution, and Creationism, a brochure on the book of the same title.
6 ^ AAAS Evolution Resources