Back in the day we only had one kind of plastic and all discs were flippy. If a disc wasn't flippy, just hit a tree or two and it would be flippy. When you wanted to throw far you threw your disc on a 7 o'clock hyzer and high in the air. It would turn over and slowly fade back. We called this a flex shot. It's a line you don't see thrown anymore. Nobody threw forehand with power because the discs weren't stable enough. We all wore Zubaz and had majestic mullets. We used our fanny packs to hold the three discs we played with. Nobody had more than three discs. If you had more than one you were considered a pro. Most people didn't even have a putter. Most people didn't even know what a putter was. Most people had a shark or cyclone, and that was it. This was the silver age of disc golf. The golden age was in the 70s when people were using superpuppies and lids from their butter bowls. You will never be as cool as those guys were. Don't even try.
In the silver age we only referred to our discs as stable or unstable. A new roc was stable. A beat roc was unstable. When we said a disc was more stable, we meant it flew closer to a new roc. We didn't say things like high speed stability or low speed stability because we were burnouts and that was high-tech science talk. If you were a brainiac you had heard the term "hyzer" before, but only once, and you didn't know what it meant. We didn't have the internet so we couldn't spend time staring into screens furiously typing feeble arguments about pointless debates regarding inconsequential issues that, in the end, didn't even matter to the people that were engaged in the debate. We had to find other ways to occupy our time. So we played disc golf. And read books that we got from a place we called a "library"... but I digress.
Stable and unstable. That was it. If someone said "more stable" or "less stable." It was clear what they meant. If someone was trying to get technical they'd say something like "actually it isn't 'less stable,' it's 'more unstable.'" This didn't bother us, because we'd just beat that guy up and take his beer. We were very thirsty back then and could always use an extra beer or two.
Then the disc manufacturers came out with the first discs that could truly be called overstable, like vipers and banshees. This blew our minds. We started throwing flex shots with the disc not released at 7 o'clock, or even flat, but on an anhyzer, ... and it still flexed back. Although we would have thought you were talking about beer if you said "anhyzer." At first we thought these discs were the result of some dark, arcane arts and it frightened us. Not disimilar to how the cavemen must have first reacted to fire, I imagine. Eventually, we got used to it, but we had difficultly talking about our new discs and the shots we made with them. The words simply didn't exist yet. Describing them as more stable didn't seem sufficient. So we'd say things like superstable. And megastable. And bigtime stable. And hardcore stable. I'm sure in Boston they said they were wicked stable, but we were midwesterners and we didn't say "wicked." We said "hardcore, bigtime." One time a guy thought he'd be cute and said "bigcore, hardtime." We beat him up and took his beer.
Over time the manufacturers started coming out with new plastics and the concept of premium plastic was invented, and then one day a girl played, and the game would never be the same. Anyway, eventually someone came up with the term overstable to describe these new discs and the way they flew. This caught on and unstable didn't seem to work as well as a term in opposition, understable made intuitive sense. Then people started using those terms, but over time we missed describing our discs as stable. By this time the internet was invented and we all called each other names over Prodigy .... oh, that might be confusing to you.
You see back in the day there were only two ways on the internet. Prodigy and AOL. Both used things we called "landlines." You'd connect your computer to the landline in your house, your "modem" would make a bunch of digital, sproingy type noises, and then you could either go to a "billboard" and spend the entire night downloading a file of what was supposed to contain a single picture of Gloria Estafan in what you were assured was a state of undress, or you could go to a "chatroom," and have real time discussions with people you didn't like. Anyway, Prodigy was a internet service provider that had a logo that was a sylized five pointed star... completely different than anything you may be familiar with. AOL was Prodigy's competition and eventually beat them out. They sent you a CD every ten minutes. It was nice. Especially if you were a disc golfer and liked to throw them like frisbees. Although they were very unstable. Or so we thought. It turned out we were wrong the whole time. They weren't unstable, they were UNDERstable. Thanks guy-whose-been-playing-the-sport-for-two-whole-months for correcting us.
As I was saying, we missed calling our discs stable, so eventually somebody figured out that if discs that turn are understable, and discs that fade are overstable, then discs that go straight must be "stable." We would have beat him up and took his beer, but this was fist said over the internet in a chatroom and we didn't know where he was. Ever since then you'll find people on the internet who insist that discs that go straight are stable. These people will reason that since a disc that flies straight is stable, then "more stable" must mean that a disc flies even more straight. If I ever figure out where these people are...
All of the preceding is 100% true.