This is another disconnect between the two camps. See, they have a source they can point back to and say "Look; it says right here Goddidit, and if you don't believe me you can argue with the author...while you're toasting in eternal hellfire."
They want us to quote some seminal, single definition that is eternally true, and they want us to nail down the target for them. Scientists and serious students (and I would add people of modest intelligence but honest intentions) have little trouble dealing with uncertainties. Isn't this really the same thing as say The Golden Rule...sure it means treat others just like you want to be treated, but it's really much more than that. We all know what the ToE is, but can any two of us agree on how it's phrased; does this make it any less true than the Golden Rule which has umpteen different phrasings in the Bible alone. Maybe we should insist on a quid pro quo and ask them to standardize their eternal truths before they come gunning for temporal knowledge.
I suggest we start by saying
The Theory of Evolution is the collective scientific understanding of developmental biology that begins with Darwin's Theory of Descent with Modification through Natural Selection. If they want to know what that means we can point them to Origin of the Species with the warning that this is all just where it starts.
Edited by Wepwawet, : Believe me, it's better this way