aquitard

noun
aqui·​tard | \ ˈa-kwə-ˌtärd How to pronounce aquitard (audio) \
plural aquitards

Definition of aquitard

geology
: a geologic formation or stratum that lies adjacent to an aquifer and that allows only a small amount of liquid to pass If the water level—and thus the pressure—drops enough, water is slowly squeezed out of the large clayey layers—called aquitards—that more or less seal the aquifer, and an aquifer's compression becomes irreversible.— Peter Bacque, Richmond (Virginia) Times Dispatch, 14 Nov. 2002

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!

First Known Use of aquitard

1965, in the meaning defined above

History and Etymology for aquitard

probably from aqui- (in aquifer) + (re)tard

Learn More About aquitard

Time Traveler for aquitard

Time Traveler

The first known use of aquitard was in 1965

See more words from the same year

Dictionary Entries Near aquitard

Aquitania

aquitard

aquiver

See More Nearby Entries 

Statistics for aquitard

Cite this Entry

“Aquitard.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/aquitard. Accessed 15 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

WORD OF THE DAY

Test Your Vocabulary

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

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