SINCE 1828

An Encyclopædia Britannica Company

planetary science

noun

Definition of planetary science

:planetology

—

planetary scientist

noun

First Known Use of planetary science

1969

Seen and Heard

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WORD OF THE DAY

anathematize

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to curse or denounce

Words at Play

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'Meat Sweats': The Competitive Eater's Worst Nightmare

They're real, but is meat the cause?

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'Diffuse' vs. 'Defuse'

Let us defuse the situation.

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Breathing Life Into 'Inspire'

The word's origins are quite literal

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Let's Talk 'Tea'

Spill it, sip it: just make it hot.

Ask the Editors

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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'

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Irregardless

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

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Weird Plurals

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

Word Games

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Merriam-Webster's New Words Quiz—Fall 2017 Edition!

You're going to have to memorize the dictionary again.

Take the quiz

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Challenging Vocabulary Quiz Returns!

No tricks, just difficult words.

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Name That Thing

Name That Thing

Test your visual vocabulary with our 10-question challenge!

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SCRABBLE® Sprint

SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

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