SINCE 1828

An Encyclopædia Britannica Company

amygdaloidal

play

adjective amyg·da·loi·dal \ ə-ˌmig-də-ˈlȯi-dᵊl \

Definition of amygdaloidal

:of, being, or containing small cavities in igneous rock that are filled with deposits of different minerals (such as chalcedony)

—

amygdaloid

play \ə-ˈmig-də-ˌlȯid\ noun

First Known Use of amygdaloidal

1797

Seen and Heard

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

show

WORD OF THE DAY

holus-bolus

play

all at once

Words at Play

alt-59c2960017c94

The Ambiguity of Pushing 'Up' and 'Back'

When you push a meeting, where does it go?

Silent Letters

When each letter can be seen but not heard

alt-59c17b8172892

'So Long': A Common But Mysterious Goodbye

Its origins are surprisingly murky.

alt-59c13729150dc

"Immune to" or "Immune from"?

Nobody is immune to this question.

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

stylized-drawing-of-woman-pole-vaulting-across-gap-to-get-trophy

Challenging Vocabulary Quiz Returns!

No tricks, just difficult words.

Take the quiz

Name that Color!

NEW! Additional colors! More obscure than before!

Take the quiz

True or False?

Test your knowledge - and maybe learn something along the way.

Take the quiz

Citation

Do you know the person or title these quotes describe?

Play the game