sac
noun
a baglike structure in an animal, plant, or fungus, as one containing fluid.
sac
1 American
[sak]
/ sæk /
noun
-
sacs
plural
Sac
2
American
[sak, sawk]
/ sæk, sɔk /
noun
-
Sacs,
plural
-
Sac
plural
SAC
3
American
[sak]
/ sæk /
Or
S.A.C.
noun
sac
1
British
/ sæk /
noun
SAC
2
British
abbreviation
sac
Scientific
/ săk /
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of sac
First recorded in 1735–45; from Latin saccus “bag, sackcloth”; see sack 1
Explanation
A sac is a hollow space or container. While any pocket or pouch can be called a sac, the word usually refers to a small enclosed space that occurs in nature, like a spider's egg sac or a squid's ink sac. You might put your groceries in a sack, but without the “k” a sac is smaller and attached to a plant or animal. Human fetuses grow inside an amniotic sac, and seed plants produce pollen inside sacs as well. Since the mid-1700s, sac has been used to mean "biological pocket," from the Latin root word saccus, or "bag." If you’re not sure which sac to use, it’s almost always the other one unless you’re in biology class.
Vocabulary lists containing sac
Commonly Confused Words, List 4
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Unit 2: Evolution
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The Benefits of Being an Octopus
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
"It came right to the grass, right up above the curbs and flooded the whole cul de sac really."
From BBC ● Aug. 27, 2026
The larvae can alter the pH of the sac walls, causing the resilin to expand or contract.
From Science Daily ● Jul. 27, 2026
In a dark room, a doctor pointed to an hourglass shape glowing on the ultrasound screen: There was her amniotic sac, funneling into her dilated cervix, and there was their tiny daughter’s foot, dipping out.
From Salon ● May 27, 2026
Then came the worst part: I passed the amniotic sac.
From The Wall Street Journal ● May 13, 2026
Leonard Hayflick had an especially personal connection with his cell line, WISH, which Gartler had listed as contaminated: he’d grown it using cells from the amniotic sac in which his unborn daughter had once floated.
From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot
In nearby Sac City, Crystal Hanrahan was watching the case unfold when she got an idea.
From The Wall Street Journal ● Nov. 26, 2025
"We've got to flush this one down the toilet and get ready for Sac," said Kerr, whose side face the Sacramento Kings in their next match.
From BBC ● Jan. 21, 2025
Boys and girls cross country qualify for CIF Finals next Saturday at My Sac.
From Los Angeles Times ● Nov. 17, 2024
“Trump stood up for the people,” said Brett Potthoff, 30, an engineer from Sac City, Iowa, who considered caucusing for Mr. DeSantis but ultimately said he would support Mr. Trump.
From New York Times ● Jan. 21, 2024
“Omaha, Nebraska. Sac City, Iowa. Alexandria, Indiana. Darwin, Minnesota. Hollywood, California. Alliance, Nebraska. Okay. Those are the locations of all the things she—well, or whoever read this book—found interesting.”
From "Paper Towns" by John Green
Defra says it may not be necessary to make this area of maerl beds an SAC, "nor is there a requirement, to protect all examples of a species or habitats."
From BBC ● Jul. 31, 2026
At Mount SAC, for instance, classrooms have high-tech mannequins that can be programmed to blink, shriek and simulate a variety of medical conditions, including heart attacks, bleeding, respiratory failure — even giving birth.
From Los Angeles Times ● Oct. 6, 2025
“Once I was in Mount SAC, it was a no-brainer to go to a community college,” he said.
From Los Angeles Times ● Oct. 6, 2025
The situation has already led to limits being placed on housebuilding along SAC rivers.
From BBC ● Jun. 24, 2025
The red phone put him in direct touch with SAC wings all over the globe.
From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin
The Sacs and Fox mined and smelted 60 tons of lead for Shreve.
From Time Magazine Archive
The tribes, or rather fragments of tribes, represented at this meeting, were the Ottawas, Ojibwas, Pottawattamies, Miamis, Sacs, and Wyandots.
From The Conspiracy of Pontiac and the Indian War after the Conquest of Canada by Francis Parkman
It is also extending down the river, among the Sacs and Foxes.
From Harper's New Monthly Magazine, Vol III, No 13, 1851 by Various
A chief of the Kiscoquah band of Sacs or Sauks, and head chief of the combined Sacs and Foxes.
From Descriptive Catalogue of Photographs of North American Indians by W. H. Jackson
A description of heaven—by Wampasha, an Iowa Indian—was found in the diary of Reverend S. M. Irvin, a devoted missionary among the Iowas and Sacs.
From Legends of The Kaw The Folk-Lore of the Indians of the Kansas River Valley by Carrie de Voe
The sacs survived pressures equal to those found at depths of more than 400 meters, which is far deeper than the larvae normally travel during their daily migration.
From Science Daily ● Jul. 27, 2026
Caitlin and Grace had been believed to be fraternal twins because they developed in different amniotic sacs, but doctors found their markers were exactly the same while assessing Grace as a potential stem cell donor.
From BBC ● Jul. 1, 2026
In another chapter, Mr. Haskell follows the path of an owlet moth into the cranefly orchid’s flower and lets us watch how sacs of pollen attach themselves to the insect’s eye.
From The Wall Street Journal ● Apr. 17, 2026
The spiders’ white egg sacs, usually laid between October and November, are often attached to leaves, tree bark and flat structures and contain 400 to 500 eggs, according to Jorowatch.
From Los Angeles Times ● Apr. 9, 2026
This wasn’t too difficult, as the younger boys took one look at the shiny, wrinkled gray sacs and turned away in horror; you couldn’t have paid them to put one in their mouths.
From "The Evolution of Calpurnia Tate" by Jacqueline Kelly
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
