What about "tree nail" or trunnel... I could be wrong, but I doubt there is anyone alive using these terms. What say you Northern Hewer!?1?

I like "peg."
"Pin" sounds/ conjures up images of the metalic for me. But that's just me and likely reflects my woodworking history.

I did not pay paricular attention to pegging during my recent barn surveys. But I do remember most pegs had a rustic-looking nature... I don't believe I saw anything nice and smooth like turned pegs. And I think everything was tapered and protruded a good distance from the timber.

I don't recall seeing unpegged braces, but have heard of the practice.

And regarding "steel plates"... I know I've read this and seen diagrams in books. The thick plate had a concave/chamfered set of holes. The peg was rived to approx. diameter and then pounded through... I don't know how historically accurate this really is. Wouldn't it make a poor and weakened peg from all the pounding?? Straight grained wood should have been quite easy to rive to an approximate diameter. A block plane could have been employed if you really needed to get it perfect.

As far as draw-boring, I assume the only way to tell if a joint was draw-bored would be to dissasemble it. But would tapered pegs be used on a non draw-bored joint? I would think a slight chamfer would do fine on a non draw-bored joint, but I don't ever recall seeing chamfered pegs, only long tapers. Does that mean they're all draw-bored joints?

"Tree nail" is an interesting word/phrase. I have often wondered if siding/boarding was ever attached w/ pegs. Nails were costly luxurys back in the day. Has anyone ever heard of boards being attached w/ pegs? If you bored holes at slight downward( or even opposing) angles, I'd think you could attach wall/ roof boards this way.