76 Must-Know Shapes, Shape Adjectives and Phrases with Shapes

You’re about to learn some useful shapes and shape adjectives. For even more English vocabulary, check out Maths Vocabulary in English: Do You Know the Basics?.

OK. Take a look at this image. Can you describe it?

Describing simple shapes in English (especially when they’re 3D) isn’t as easy as it seems.

In this post, you’re going to:

1. Learn words for common 2D and 3D shapes in English.
2. Learn some shape adjectives to describe objects more generally.
3. Learn some common English idioms and phrases with shapes.
4. Laugh at some silly pictures.

Enjoy!

Common 2D Shapes

Four-Sided Shapes

Square

noun — square
adjective — square

Phrases with “Square”

We can talk about a square meal, meaning a proper meal that will kill your hunger and make you feel nice and happy and ready to take on the world. It may or may not include hummus.

Rectangle

noun — rectangle
adjective — rectangular

Parallelogram

noun — parallelogram
adjective — parallelogramatic*

*No one knows this. I actually had to Google it.

OK. This may not be the most useful shape in the world. But it’s kind of pretty, right?

Round Shapes

Circle

noun — circle
adjective — circular

Phrases with “Circle”

We use “circle” in lots of different phrases.

Here are some of the most common ones:

A vicious circle — When something bad causes something else bad to happen, which then causes something else bad to happen. Forever.

Think about people getting further and further into debt or when people argue, making each other angrier and angrier.

Go around in circles — When you do something for a long time but achieve NOTHING!

Like when you’re trying to change the settings on your phone so that it stops waking you up in the middle of the night telling you about the royal wedding. But you can’t find the “turn royal wedding off” button. So after an hour of trying to fix the problem, you just give up because you’ve been going around in circles for an hour.

Inner circle — This is an exclusive or elite group at the centre of power. Maybe it’s something big, like a whole country (the president’s inner circle) or something smaller like a company (the manager’s inner circle). People in an inner circle are usually quite secretive.

Semicircle

noun — semicircle
adjective — semicircular

We use this a lot when talking about seating — perhaps in a theatre or just when kids are sitting around a teacher:

“Come on, kids. Sit in a semicircle, and I’ll read you a story.”

Oval

noun — oval
adjective — oval

Phrases with “Oval”

The US president’s office is called the Oval Office. I just had a look on Google and yes — it’s definitely shaped like an oval.

Do you like cricket? No? Me neither. But one of the most famous cricket grounds in the UK is called The Oval.

When we were kids, my Dad took my brother and me to watch a cricket match there. We were bored after an hour.

Five hours later the cricket playing stopped, and we could finally leave. I asked my Dad who had won the match.

“Oh, the match isn’t finished yet,” he said. “They’ll be playing for another two or three days.”

Seriously? Cricket is weird.

Three-Sided Shapes

Triangle

noun — triangle
adjective — triangular

Phrases with “Triangle”

Love triangle — Bob likes Yasmine, but Yasmine’s more interested in Jo. Jo doesn’t like anyone (except for his cat, Timi, who likes sleeping, mostly). Bob, Yasmine and Jo are trapped in a love triangle! The perfect set-up for soap operas.

The Golden Triangle — This is the name of a part of Asia that covers where Thailand, Laos and Myanmar meet.

There are different types of triangle:

Equilateral triangle

Equilateral triangle — all the sides are the same length, and all the angles are the same.

Isosceles triangle

Isosceles triangle — two sides are the same length, and two of the angles are the same.

Right-angled triangle

Right-angled triangle — one of the angles is 90 degrees.

Shapes with More Than Four Sides

Pentagon

noun — pentagon
adjective — pentagonal

We all know about the Pentagon, right?

It seems US government institutions like naming things after shapes.

Hexagon

noun — hexagon
adjective — hexagonal

Octagon

noun — octagon
adjective — octagonal

Phrases with “Octagon”

In some institutions, like schools and universities, you might find the octagon, which is an octagonal space, perhaps with grass in it, perhaps not.

You can also have an octagon theatre. It’s a theatre in the shape of an octagon. Obviously.

Common 3D Shapes

Cone

noun — cone
adjective — conical

Phrases with “Cone”

We have ice cream cones. Probably because they’re shaped like a cone.

And of course, there are pine cones:

Cube

noun — cube
adjective — cubic

Phrases with “Cube”

We see cubes EVERYWHERE!

Ice cubes:

Rubik’s cube:

And the rapper, Ice Cube:

We also use “cubic” to describe three-dimensional areas, e.g., cubic centimetres (cm³), cubic metres (m³), etc.

Cylinder

noun — cylinder
adjective — cylindrical

Pyramid

noun — pyramid
adjective — pyramidal*

*This is technically the adjective form of “pyramid,” but nobody uses it. We just say “pyramid-shaped.”

We all know about these beauties:

But I can’t talk about pyramids without thinking about one of my favourite songs, Pyramid Song.

Sphere

noun — sphere
adjective — spherical

Phrases with “Sphere”

Public sphere — A place or platform where people can get together and discuss social and political issues. This can be virtual, like social media, physical, like a town hall, or abstract:

“He’s retiring from the public sphere.”

Sphere of interest — Google defines this as “A country or area in which another country has power to affect developments though it has no formal authority.” I define it as “Places that powerful countries can use to make themselves more powerful.” Politics is fun!

Disc

noun — disc
adjective — disc-shaped

Less Common Shapes

Diamond

noun — diamond
adjective — diamond-shaped

Heart

noun — heart
adjective — heart-shaped

Also, ’90s kids will remember this: Heart-Shaped Box

Kite

noun — kite
adjective — kite-shaped

Star

noun — star
adjective — star-shaped

Spiral

noun — spiral
adjective — spiral

Phrases with “Spiral”

There are spiral staircases:

Spiral out of control — This is when a series of events becomes more and more chaotic, and
the situation gets completely out of control. I’d imagine this happens a lot at children’s birthday parties. Not that I’d know — I like to avoid large groups of children. So much chaos!

A downward spiral — This is when a bad thing just gets worse and worse (similar to “vicious circle,” above). I always think about addiction when I think about this phrase. When someone gets addicted to drugs or gambling or cheese, it just gets worse and worse. They’re stuck in a downward spiral.

Downward Spiral is also the name of one of the best albums ever created. Here’s a song you might recognize from it.

Did you notice that the adjective form of many of these contains “-shaped”?

In fact, “-shaped” is really useful. You can add it to anything!

• Bottle-shaped
• Hand-shaped
• Leaf-shaped
• Walrus-shaped

When we’re describing more complicated, less geometric objects informally, we often use a phrase like “sort of,” “kind of” or “like” to help the listener understand that we’re describing something quite abstract:

“It’s a sort of egg-shaped thing.”

“Her dress was really weird — it was, like, fish-shaped. Seriously!”

Shape Adjectives to Describe Objects

Bent

Bent — not straight and with a sharp angle

Curved

Curved – not straight, like the side of a circle

Wavy

Wavy — with repeated curves

Angular

Angular — with sharp corners or points

Symmetrical

Symmetrical — the same on both sides, a mirror image of itself!

Bulbous

Bulbous – sort of fat and round. I always just think of a nose.

Concave

Concave – going inwards, like a cave

Convex

Convex – going outwards, not like a cave

Flat

Flat – this is usually used to describe a surface. It means the surface is completely 2D.

Round

Round – like a circle or a sphere!

Forked

Forked – When one line becomes two! Snakes have forked tongues. You can also have a fork in the road.

Pointy

Pointy – with a sharp end, like a sword.

Tapered

Tapered – getting thinner at the end

Twisted

Twisted – when the shape is changed by bending or turning

Like this:

Or this:

Get the idea?

Thick

Thick – when opposite sides are far apart.

Thin

Thin – when opposite sides are near.

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There you go: (pretty much) all the shapes in English plus shape adjectives and idioms!

Now, you’re ready to describe this picture:

Can you do it?

Use the shape words you’ve learned to describe the picture and leave your answer in the comments.

I’ll let you know how you did!

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