18 Fancy Words for Specific Shapes

Use anguilloform to describe something eel-shaped.
Use anguilloform to describe something eel-shaped. / ilbusca/iStock via Getty Images Plus

Circle, square, triangle—boring! There are so many more shapes than those in nature. Good thing there’s a rich vocabulary of fancy scientific words for shapes. Most of them don’t get much use, which is a shame. Get to know a few of these, and describe your world with lexical flair.

1. Acicular // Needle shaped

Acicular is used by botanists to describe leaves with a long pointy shape and by mineralogists in talking about crystals.

2. Acetabuliform // Saucer shaped

Occasionally useful in botany or geology. Your hip socket also goes by “acetabulum.”

3. Anguilliform // Eel shaped

Anguilliform locomotion—forward movement caused by sideways undulation—is fascinating to physicists.

4. Calceiform // Slipper shaped

Some flower petals are calceiform—they look like little shoes. Not to be confused with calciform (shaped like pebbles).

5. Clithridiate // Keyhole shaped

Not much seen outside of 19th century descriptions of invertebrate fossils, but fun to say.

6. Cochleate // Snail shaped

Plant parts or chemical compounds can be cochleate—rolled into a spiral like a snail shell. Also cochleate, the spiral tube in your inner ear known as the cochlea.

7. Fabiform // Bean shaped

Here’s a good sentence from a 1909 book on rocks: “iron often inclines to the pisiform and fabiform.” (Pisiform means pea shaped.)

8. Falcate // Sickle shaped

The butterfly known as the Falcate Orangetip has wings that curve and taper to a pointed tip.

9. Flabellate // Fan shaped

Insects with flabellate antennae look like they have two little fans attached to their head. If you prefer Greek roots over Latin, another word for this is rhipidate.

10. Hastate // Spearhead shaped

Leaves or anatomical structures that look like spearheads are hastate, from the Latin hasta for spear.

11. Hippocrepiform // Horseshoe shaped

Here’s a convenient word for horseshoe shaped … that takes just as long to say as “shaped like a horseshoe.”

12. Hordeiform // Barleycorn shaped

If it looks like a grain of barley, it’s hordeiform.

13. Ichthyomorphic // Fish shaped

Goldfish crackers aren’t fish, but they are ichthyomorphic.

14. Lachrymiform // Tear shaped

Apple seeds and watermelon seeds are lachrymiform.

15. Reniform // Kidney shaped

Kidney beans may be reniform, but actual kidneys are fabiform.

16. Scaphoid // Boat shaped

The most commonly broken bone in the wrist, the scaphoid, looks like a little boat.

17. Scyphoid // Cup shaped

The ancient Greek skyphos, a two handled drinking vessel, gives its name to cup-shaped objects such as jellyfish, of the biological class Scyphozoa.

18. Xiphoid // Sword shaped

From the Greek xiphos for sword. If you prefer Latin roots, there’s ensiform (from Latin ensis). The little piece of pointy cartilage at the bottom of your sternum where the lowest ribs meet is called the xiphoid process.

A version of this story ran in 2014; it has been updated for 2021.