SINCE 1828

An Encyclopædia Britannica Company

gnomon

noun gno·mon \ ˈnō-mən , -ˌmän \

Definition of gnomon

1 :an object that by the position or length of its shadow serves as an indicator especially of the hour of the day: such as

a :the pin of a sundial

b :a column or shaft erected perpendicular to the horizon

2 :the remainder of a parallelogram after the removal of a similar parallelogram containing one of its corners

See gnomon defined for kids

Recent Examples of gnomon from the Web

The original clock is missing its gnomon, the part of a sundial that casts a shadow, but an 18th-century museum curator described it having one in the shape of a pig’s tail, so Parslow re-created that, too.

— National Geographic, "Ancient Sundial Shaped Like Ham Was Roman Pocket Watch," 19 Jan. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'gnomon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Illustration of gnomon

Origin and Etymology of gnomon

Latin, from Greek gnōmōn interpreter, pointer on a sundial, from gignōskein

NEW! Time Traveler

First Known Use: 1546

See Words from the same year

Learn More about gnomon

See words that rhyme with gnomon

Seen and Heard

What made you want to look up gnomon? Please tell us where you read or heard it (including the quote, if possible).

show

WORD OF THE DAY

adversity

play

serious difficulty or misfortune

BROWSE DICTIONARY

Test Your Vocabulary

The Exceptions Quiz III

Which of these words does not mean "nonsense"?

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ

SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Words at Play

alt-59ea52ed7b96f

Learned Fools: On Names for Students

Where did we get 'freshman' and 'sophomore'?

alt-59e900afadac6

The Synonyms 'Discover' and 'Invent'

In the past, you could invent fruit.

alt-59e8c3440f453

I'll Have the Us(ual)

Shortening 'usual': easy to say, hard to spell

alt-59e77dc36c593

The Origins of 'Lobbyist'

From the front hallways to the back rooms

Ask the Editors

video-title-words-of-the-year-1066

Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless

Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals

Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

one-green-toy-robot-amidst-many-red-toy-robots

The Exceptions Quiz III

Which of these things doesn't belong?

Take the quiz

knupfer-painting-solon-before-croesus

Forms of Government Quiz

Name that government! Or something like that.

Take the quiz

Spell It

Can you spell these 10 commonly misspelled words?

Take the quiz

SCRABBLE® Sprint

SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game