Is evolution true? Well, first, what is it?

Is evolution true? That depends. One thing it surely depends on is what evolution is.

Unfortunately, there are several meanings of the word, and several ways in which it is used, and two people who are having a conversation about the subject may be using different meanings without knowing it. That doesn't make it likely that the conversation will be helpful.

Here's one attempt, as part of an essay on the subject, to identify three different meanings of "evolution."

Thanks for reading.