You're absolutely right! In everyday speech, "theory" often gets used to mean a guess or an idea that's not necessarily backed up by evidence. This is very different from how scientists use the term "theory".

A scientific theory is a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.

Here's how a scientist might explain the difference:

"When people say 'theory' in everyday conversation, they often mean something like a hunch or a guess. But in science, a theory is much more than that. It's a comprehensive explanation that's been rigorously tested and supported by a large body of evidence. For example, the theory of evolution is not just a guess; it's a well-supported explanation for the diversity of life on Earth, backed by countless observations and experiments."

Here are some key points a scientist might emphasize:

* Scientific theories are not just guesses. They are based on a large body of evidence and have been rigorously tested through experimentation and observation.

* Scientific theories are constantly being refined and updated. As new evidence emerges, theories can be modified or even replaced.

* Scientific theories have predictive power. They can be used to make predictions about future observations.

In short, a scientist might say that a scientific theory is the best explanation we have for a particular phenomenon, based on the available evidence. It's not just a hunch, but a well-established and supported explanation.