There are 2 main definitions of sac in English:


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1A hollow, flexible structure resembling a bag or pouch: a fountain pen with an ink sac
More example sentences
  • Rain Reviva is a system of flexible plastic sacs for storing rainwater - or recycling waste water - under the house.
  • As the air filled the sac, the balloon took on an impossibly long shape.
  • Reseal the plastic sac and leave it rocking for 1 h at room temperature.
bag, pouch, bladder, blister
technical bursa, acinus, follicle, cyst, saccule, utricle, vesicle, vesica, vesicula, theca, liposome
1.1A cavity within an organism, enclosed by a membrane and containing air, liquid, or solid structures.
More example sentences
  • In the field of biology, biochemists have been studying vesicles, the small membrane sacs found within cells.
  • Fistulas commonly extend from the rectal sac to the perineum or genital tract in a female, or to the urinary tract in a male.
  • If chemicals are splashed into the eye, the eye and the conjunctival sacs should be washed out immediately with copious amounts of water.
1.2The distended membrane surrounding a hernia, cyst, or tumour.
More example sentences
  • If the leak persists or the aneurysmal sac enlarges, intervention becomes necessary.
  • In the vicinity of this mass, there was a hernia sac.
  • As people get older, fluid-filled sacs, called ‘cysts,’ can form in the kidneys.


mid 18th century (as a term in biology): from French sac or Latin saccus 'sack, bag'.



More example sentences
  • The cnidarians (hydra, jellyfish, and sea anemones) and helminths have a sac-like digestive system with a single opening.
  • Chlorosomes, found only in green photosynthetic bacteria, are large supramolecular sac-like complexes that are attached to the cytoplasmic side of the inner cell membrane.
  • The saccular or cystic form is the most severe type and is characterized by a ballooning of the bronchi with fluid-filled, sac-like dilatations.

Definition of sac in:

There are 2 main definitions of sac in English:


Line breaks: SAC


Senior Aircraftman or Senior Aircraftwoman.

Definition of sac in: