The board's compromise adds the term "scientific theory" not just to evolution but to other areas of science, including the theories of atoms, cells and electromagnetism. This was done for one purpose: to allow the confusion over the term "theory" to cloud the legitimacy of evolution as the only accepted scientific explanation for life's origins. The scientific theory of plate tectonics doesn't inspire the same religiously grounded backlash.
Scientific theory is not a guess or a mere hypothesis. It is a framework that explains observable facts. In biology, evolution is the unifying theory that continues to be reinforced and verified by ever more sophisticated research. There is no credible alternative scientific theory. Other options, such as intelligent design or creationism, are a matter of personal beliefs or religious teachings. They could be discussed in an appropriate educational setting, but they do not belong in a science curriculum.Yay!