sac
1 Americannoun
noun
plural
Sacs,plural
Sacnoun
noun
abbreviation
Other Word Forms
- saclike adjective
Etymology
Origin of sac
First recorded in 1735–45; from Latin saccus “bag, sackcloth”; 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.
In these cases, the sheer size of the cell and the presence of a large yolk sac prevent the actin ring from fully closing.
From Science Daily • Feb. 28, 2026
Meanwhile, the cul de sac, a street design much in favor with the architects of suburban developments, have become artificial catchments for these highly flammable weeds.
From The Wall Street Journal • Nov. 17, 2025
Battling strong currents, Ralph Pace captured this image of a swell shark egg case, revealing a glowing embryo, complete with gill slits and a yolk sac.
From BBC • Oct. 14, 2025
At the hospital, Nusslock said she was diagnosed with a premature rupture of the membrane of the amniotic sac — a dangerous complication in which an abortion is a recommended treatment.
From Los Angeles Times • Sep. 30, 2024
Inside the sac was something that looked like a person, but a person with two heads, with twice as many arms and legs as it should have.
From "Coraline" by Neil Gaiman
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.
