Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

See What's Trending Now See More Trending Words

pentahydrite

noun pen·ta·hy·drite \ ˌpentəˈhīˌdrīt \

Definition of pentahydrite

plural -s
:a mineral MgSO4.5H2O consisting of hydrous sulfate of magnesium isostructural with chalcanthite and containing less water than epsomite

From the M-W Editors

image2143067130
9 Slang Words With Academic Origins
alt-59bab5dbb4997
Trending: 'Bodega' Startup Draws Criticism, Mockery
alt-59bff395cf879
What's Going On With 'Nonplussed'?
video-title-words-of-the-year-1066
Words of the Year: 1066

There's more!

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!
Already a subscriber? Log in.

Origin and Etymology of pentahydrite

penta- + hydr- + -ite

Seen and Heard

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

show hide

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

glabrous

play

smooth or hairless

Get Word of the Day daily email!

TRENDING NOW

  1. bodega "Don’t mess with the beloved bodega."

  2. carceral Of, relating to, or suggesting a jail or prison

  3. allegory No spoilers!

  4. hurricane 'A tropical cyclone'

  5. rescind To take away; cancel; repeal

SEE ALL

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

alt-59bff395cf879
What's Going On With 'Nonplussed'?

Its recent usage is hard to shrug off.

alt-59bad350d88f1
Welcome to the New Words

From 'hive mind' to 'sriracha'

image2143067130
9 Slang Words With Academic Origins

Class is in session.

image624847743
8 Foods Named After Real People

A delicious collection of eponymous foods

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'

payday
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-logo
Name that Color!

NEW! Additional colors! More obscure than before!

Take the quiz
How Strong Is Your Vocabulary?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Take the quiz
Syn City
Syn City

Build a city of skyscrapers—one synonym at a time.

Play the game