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Imagine a 3D cylinder, like a can. Now imagine that almost like an axle spot for a wheel, there's a hole shaped in a perfect circle going down the cylinder. That's the shape I have to figure out the name for. Mathematical names are preferred, but any name works!

Peter Mortensen
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RandomGuestNameHere
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  • If the bore of the hole is axial ( is that what you meant by"going down the cylinder"?), then it, too, is a cylinder. – TimR Feb 24 '15 at 21:40
  • Any hole bored through a solid is a cylinder, although it might have ends which need special description. – Andrew Leach Feb 24 '15 at 21:44
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    There's only 1D in cylinder. – Jim Reynolds Feb 24 '15 at 21:46
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    It's basically a 2-dimensional concentric circular torus extended in a third dimension to make a hollow cylindrical solid. I don't think there's a special term (like frustrum for cones) that describes this. – John Lawler Feb 24 '15 at 21:51
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    What about wheel? – anemone Feb 24 '15 at 21:53
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    Related but not the same: http://english.stackexchange.com/questions/39196/what-do-you-call-a-disk-with-a-hole-in-the-middle – Mitch Feb 24 '15 at 22:02
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    I think you call it a "pipe". (Well, actually, "cylinder" is the common term, unless it's exceptionally long.) – Hot Licks Feb 24 '15 at 22:24
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    So you mean basically like a very tall doughnut? – Janus Bahs Jacquet Feb 24 '15 at 22:37
  • Without further specification (e.g.: ratio of length to width, ratio of interior diameter to exterior diameter, relative location and orientation of the hole) you're likely to get a number of inaccurate or otherwise case-specific suggestions. Are you actually looking for a word to generally describe any object of this type, or do you have something a bit more particular in mind? – Iszi Feb 24 '15 at 23:23
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    Tube. Thick-wall or thin-wall. If cylinder is short enough, the holed variety might be called a washer. – Wayfaring Stranger Feb 25 '15 at 00:27
  • Really? You couldn't figure out the word tube? – spacetyper Feb 25 '15 at 02:53
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    A man, a worm, and a straw are topolgically equivalent. – tchrist Feb 25 '15 at 04:12
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    Mitch got it right. The three-D version of http://english.stackexchange.com/a/39225/3306 is a torus. Since the OP asked for a mathematical word, the sub-discipline is called topology. Topologically speaking, it doesn't matter how thick the cylinder is or how big the hole is. It's still a torus. – rajah9 Feb 25 '15 at 04:18
  • You ought to fill in some of your user profile, so we can tell what context your questions generally come from. – JDługosz Feb 25 '15 at 05:45
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    @rajah9: That assumes OP is doing topology. If he/she is doing geometry instead, torus would be completely wrong. – Nate Eldredge Feb 25 '15 at 06:09
  • @NateEldredge please see this entry at Wolfram Mathematica: http://mathworld.wolfram.com/Torus.html . The categorization they use is Geometry -> Solid Geometry -> Tori. – rajah9 Feb 25 '15 at 14:32
  • @JimReynolds I think you forgot how to spell "dcylindder" (note, the silent "d") – Jim Feb 25 '15 at 19:10
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    Sometimes "p" is silent, as in swimming pool. :) – Jim Reynolds Feb 25 '15 at 21:21
  • There is a shape with a hole http://en.wikipedia.org/wiki/Torus torus that could be functionally the same because it also has a hole in it. – Niklas Rosencrantz Feb 27 '15 at 03:19

13 Answers13

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A solid cylinder with an axial hole is still a cylinder. If the length of the cylinder is very much less than the diameter and the bore is small compared to the diameter it is a washer. If the length is much larger than the diameter, and especially if the bore is nearly as large as the cylinder diameter it is a tube.

WhatRoughBeast
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In technical terms, it seems that the three dimensional object would be called an annular cylinder:

A problem in generalized thermoelasticity for an infinitely long annular cylinder

Annulus is certainly a two-dimensional object in geometry describing one cross section of an open cylinder:

NOUN

technical

1 A ring-shaped object, structure, or region.

A barrel is also a common less technical reference for a bored cylinder:

A cylindrical tube forming part of an object such as a gun or a pen:

Tube, pipe and ring also offer less technical descriptions.

International Journal of Engineering Science Volume 26, Issue 3, 1988, Pages 301–306

www.oxforddictionaries.com

en.wikipedia.org

ScotM
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    Annulus appears to be 2D... – anemone Feb 24 '15 at 22:01
  • Though mathematically similar, an annulus is considered very flat (like a washer) or even 2D. Much of any depth to it and people wouldn't call it an annulus anymore. I don't have a good single word for what is desired but a 'cylinder with bored/rifled center'. – Mitch Feb 24 '15 at 22:01
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    As the other comments mention, an annulus is 2-dimensional; this object is an annular cylinder. – Nick Matteo Feb 25 '15 at 01:55
  • I recall encountering some writing by a non-native speaker that used annulus. That's unheard of in American English and I suggested ring for that particular use. – JDługosz Feb 25 '15 at 05:39
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    @jdlugosz: In technical mathematical writing, annulus is the recognized term for the 2-dimensional shape, partly because ring is used in mathematics for something completely different. – Nate Eldredge Feb 25 '15 at 06:08
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Cylinder -Wiki

Open Cylinder

A cylinder -with the generating lines perpendicular to the bases, with its ends closed to form two circular surfaces- with a hole perpendicular to its base, is a right circular, open cylinder.
Its function tells us if it's a pipe, washer, bearing, beer can, ect.

Google's 4th picture hit for open cylinder:

enter image description here

Brian Hitchcock
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Mazura
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    Sorry, but this is mistaken. An open cylinder is a surface, not a 3D solid, and the image is wrong or at the very least, highly misleading. See details in my answer here. – Old Pro Dec 02 '23 at 10:10
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Colloquially, i'd just call it a hollow cylinder.

keshlam
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7

I've always considered that a Toroid

http://en.wikipedia.org/wiki/Toroid

user111727
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4

Stealing from other answers as well.

  • Tube (if it's longer than it is wide)
  • Tunnel (if it's a tube big enough to crawl or drive through)
  • Pipe (if it's long and fixed in place)
  • Hose or Conduit (if it bends)
  • Ring or Disc or Washer (if it's shorter than it is wide)
  • Straw (if you drink through it)
  • Bucket (if it has a cover on one end)
  • Bottle (if it's a bucket with the open end narrower than the closed end)
  • Can or Canister or Capsule (if it has a cover on both ends)
  • Duct (if it has junctions)
  • Barrel (if you shoot projectiles through it, or it's made of compressed wood planks, or it's a canister big enough to store a person)
  • Toroid (if its ends meet)
  • Sleeve (if it's designed to snugly surround something)
  • Coil or Solenoid (if it's made by tightly winding material around a cylinder)
  • Bushing (if it has internal, inverse screw threading)
wberry
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3

In the UK Steel Industry it is referred to as a Hollow Bar

robin
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In French, it would be called "un manchon". I found the following translations for this word: muff, sleave, bush(ing), socket. I don't know which one is the most appropriate.

Michel Fioc
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  • Tube
  • Ring
  • Pipe
  • Washer
  • Straw
  • Hollow cylinder
  • Cylindrical shell
  • Bored cylinder

Or, perhaps the most technical name for it:

  • Long round thing with a hole through it
Jim
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It's called a tube - a hollow cylinder. E.g.; gun barrels are sometimes called metal tubes; plastic sewer pipes get addressed as tubes; and architects get the privilege to call tunnels tube-shaped structures.

Wicdz
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In Mathematics, the shape the OP describes is a cylindrical shell, which is a 3D solid more colloquially called a "tube" or "pipe" or some of the other terms @wberry listed.

The term "cylinder" itself is now quite ambiguous, referring both to a 3D solid in some contexts and the surface area of such a solid in other contexts. Where it refers to a surface area, the surface area includes the areas of the disks at either end. The term open cylinder refers to the surface area of just the sides of the solid, without the end disks. An open cylinder is not a 3D solid.

Old Pro
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This is what I remember using in geometry class: "coaxial cylinders". Pipe is correct too. Disclaiming that the hole is not implied there. This question is very close to yours, check it out.

Community
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hungryKoala
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In mathematics, prism is used to describe a 2D object projected along a third axis to form a 3D object. As long as the bores are coaxial and concentric, call it a annular prism. If the third axis is perpendicular to the 2D plane, it is a right annular prism. This will work in any technical context where you want a generalized term for this concept.

However, once you have a specific context or example, annular prism becomes unwieldly, and I'd just call any specific one of these a cylinder.

So if you want to talk about automating FEA grid optimization for these forms, annular prism is the way to go. But when it comes time for the machinist to make one, they make you a cylinder.

Note, toroidal prism is a type of polyhedron - it's an easy mistake to make.

You also want to make sure there aren't any ideas of light refraction attached.

related - https://math.stackexchange.com/questions/2837256/what-do-you-call-a-3d-annulus-cylindrical-shell-and-parts-of-it

"Free vibration analysis of bi-directional functionally graded annular plates using finite annular prism methods"

When light refraction is the central idea, don't use annular prism - use prism rod (lead with the word prism when talking about light refraction) - https://www.swiftglass.com/portfolios/prism-rods.

Phil Sweet
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