only one that goes all the way through it

One. A straw is just an elongated donut, and I think you’d be hard-pressed to find someone who insists that donuts have two holes.

2. If you had one side closed off it would have one hole. Open up the other side you got 2

One, because although there's an opening on each end, it is a single passage. To have two holes it would have to look something like an extruded figure-eight.

1 hole. Look at it like a cylinder, but make a hole all the way through, however long the cylinder is will just make for a deeper hole

2 holes, one cavity

So a donut has two holes too..?

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This made my brain turn upside down

That’s a whole formula where you take the diameter of each hole multiply by length, then divide by PI, then subtract the circumference = 2 holes

So you say a donut has two holes, and a ring has two holes, and literally nothing is able to have one hole?

Thank you! I know it's Reddit but I'm actually a little frustrated by all the people saying 2

A hole has 1 hole

Exactly half the number of grooves a record has.

But to be a hole it has to go trough something, which in your theory makes it two holes. So give an example of something that has 1 hole