I guess I need to do some aerobatic learning because I have always understood a barrel roll to be a roll maneuver which is using pitch input to scribe a corkscrew pattern through the air which when done properly is a 100% 1G maneuver.

Your right. Properly done it is benign. But if someone with low or no experience does one and things go bad, they can go very bad in a hurry.
An airplane rated for aerobics will have a much larger safety margin to help the pilot sort it out.

Just don't do that any more.
 

https://youtu.be/Ra_khhzuFlE?t=61

Technically, a barrel roll has very similar G loading to an inside loop. 3 to 3.5 on the pull up and pull out of the loop portion. Almost no G at the top.

Only an aileron roll properly done is a 1 G to a zero G load and back to 1 G.

That's not the traditionally accepted meaning of "barrel" roll. If it was, there would be no difference between saying "barrel" roll and "aileron" roll.

I think my post already indicated that I understood that (now) but to me there still can be a difference. What I described is not constant altitude. What I (now I know incorrectly) understood to be a true aileron roll scribes a perfectly straight longitudinal line while rolling which has to include something less than 1G while inverted.

Aileron roll: pull nose up, neutralize pitch input, aileron only and nose drops, close to 1G through rolling

Slow roll (IAC competition name): flight path constant, -1G inverted with constant rudder, elevator, and aileron input changes for a constant flight path and roll rate.

Barrel roll as others have said, combination of loop and roll with ~3G pull into a loop at the entry

https://www.iac.org/legacy/aerobatic-figures

I wonder who the first guy was to do a roll?

Yeah too many rolls terms to cross up - barrel, aileron, slow, ballistic, lobster, etc. The only one that has real standards is the one where your flight path maintains straight and level as you roll, which should see a perfect +1G to -1G transition. Some call this a "slow" roll, but in the competition world, it's just called an "aileron" roll, since there are only two types of rolls - aileron and snap, and aileron rolls must always be done on a constant line. In the recreational acro world, "slow" roll means the comepetition style roll, "aileron" means the pitched up positive (1G) roll, and barrel means looping and rolling together.

Rolls
 

As i posted in another thread a few days ago, some time ago IAC tampered with roll terminology.
Maybe we could use Hoover Roll as a better way to avoid confusion. Most at some point have seen this roll performed in the Shrike Commander as well *** several other types. Hoover did the roll on at least one occasion while pouring ice tea with the airplane inverted for the camera. No significant heading displacement, positive G all the way around.
A barrel roll changes heading either 45 degrees or 90 degrees(military) and as previously noted involves approximately as much G load as a loop.

I think his name was Adam.

Best to talk your wife into letting you spend a few hours with Patty Wagstaff in Florida. Lots of ways to skin a cat, but you don't want to de skin your 9 or even wrinkle it.

I have never known anyone that took aerobatic flight training with Patty that felt it was anything other than a really great use of time and money.
One of her instructors used to own an RV.