A pouch or pouchlike structure in a plant or an animal, sometimes filled with fluid.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "sac" in a sentence
"The excess amniotic fluid was then removed from the recipient twin sac, and antibiotics were placed into the uterine cavity to decrease the risk of infection."
"I had been walking home through the wilderness that separated my cul-de-sac from the grocery store, it was a walk I had taken hundreds of times over the past five years, when I tripped."
"The sac is filled with foam blocks that arrive all packed tight."