In common parlance, yes.

Here is a good description of the difference in meaning of the word "theory" between common parlance and science from the American Museum of Natural History:

"In everyday use, the word "theory" often means an untested hunch, or a guess without supporting evidence. But for scientists, a theory has nearly the opposite meaning. A theory is a well-substantiated explanation of an aspect of the natural world that can incorporate laws, hypotheses and facts."