I found this article, and after seeing so many incorrect posts, photos, and related articles all over the internet, I decided to fight back.
Original article found here (open in separate window).
Let’s break these down, shall we?

1. Coffin & ballerina often get used interchangeably. These are *technically* ballerina, as coffins are narrower on the free-edged sides (those not touching the actual finger).
2. Very close, but I think that edge on the left side is only due to the fact that all of these are computer-generated. As you can probably assume, true ovals are actually oblong, and curved the whole perimeter.
3. Again, very close. If you look at this closely, you’ll see the sidewalls curve in very slightly. No. A true square is just that; 90 degree angles on both corners, perfectly straight across.
4. This is the worst offender. I am constantly battling the uninformed masses about real stilettos. Stiletto nails is not just any pointed &/or long nail; it is really long, really tapered, and comes to a thin point at the tip. They are named after the shoe, and follow very similar shaping. This photo is more of an elongated almond.
5. No. Just no. That is NOT a squoval. Squovals are a flat top and rounded corners. I don’t know what this shape is, but it is NOT a squoval.
6. Close… once again. True almonds do not have flat tips. Your tip should be pointed, but softened with a buffer (literally like the nut).
7. “Pointed nails” is a descriptor, not a shape. If you really want something like this, maybe we can call it “gabled” (like the roof).
8. Again, the edges in the pic are probably computer-generated. True round nails are a more gently-rounded curved than an oval. Think: half a basketball…

Although not pictured, I also have done quite a few Tapered Square sets…
I will be taking some time in-house very soon to sculpt out these shapes properly, but for now, most of them are in an album on FB — here.