amniotic sac

am·ni·ot·ic sac
UK, contemporary/ˌæm.niːˌɒt.ɪk ˈsæk/UK/ˌam.niːˌɒt.ɪk ˈsak/UK/ˌæm.niːˌɔːt.ɪk ˈsæk/UK/ˌam.niːˌɔːt.ɪk ˈsak/

noun

The sac in which the foetus develops in mammals, reptiles, and birds.

“Near-synonym: amnion (meronymy, holonymy, or embryological sequence seem to vary by who is defining the two)”

Similar
bag of watersmembranesamnionamnios
Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounamniotic sac (plural amniotic sacs)

plural amniotic sacs

  1. anatomyThe sac in which the foetus develops in mammals, reptiles, and birds.

    Near-synonym: amnion (meronymy, holonymy, or embryological sequence seem to vary by who is defining the two)

    Synonyms: bag of waters, membranes, amnion

Synonyms & antonyms

nounThe sac in which the foetus develops in mammals, reptiles, and birds.

Similar
bag of watersmembranesamnion

More synonyms by meaning

nounthin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)

Similar
amnionamnios
Broader
sac
Also see
amnionamniosbag of waters

Synonym sets from Open English WordNet, CC BY 4.0.

Translations

Arabic كِيس سَلْوِيّ, سُخْد
  • كِيس سَلْوِيّ (kīs salwiyy)sac in which foetus develops — see also amnion
  • سُخْد (suḵd)sac in which foetus develops — see also amnion
Catalan sac amniòtic, sac àmnic
  • sac amniòticsac in which foetus develops — see also amnion
  • sac àmnicsac in which foetus develops — see also amnion
Chinese Mandarin 羊膜囊
  • 羊膜囊 (yángmónáng)sac in which foetus develops — see also amnion
Estonian lootekott
  • lootekottsac in which foetus develops — see also amnion
Finnish sikiöpussi
  • sikiöpussisac in which foetus develops — see also amnion
French sac amniotique
  • sac amniotiquesac in which foetus develops — see also amnion
German Fruchtblase, Fruchtsack
  • Fruchtblasesac in which foetus develops — see also amnion
  • Fruchtsacksac in which foetus develops — see also amnion
Greek αμνιακός σάκος
  • αμνιακός σάκος (amniakós sákos)sac in which foetus develops — see also amnion
Hebrew כיס השפיר
  • כיס השפיר (kis hashafír)sac in which foetus develops — see also amnion
Hungarian magzatburok
  • magzatburoksac in which foetus develops — see also amnion
Icelandic líknarbelgur
  • líknarbelgursac in which foetus develops — see also amnion
Italian amnios
  • amniossac in which foetus develops — see also amnion
Latin membrāna fētālis
  • membrāna fētālissac in which foetus develops — see also amnion
Persian مشیمه, یاره
  • مشیمه (mašime)sac in which foetus develops — see also amnion
  • یاره (yâre)sac in which foetus develops — see also amnion
  • آتون (âtun)sac in which foetus develops — see also amnion
  • یارک (yârak)sac in which foetus develops — see also amnion
Polish błona płodowa, błona jajowa
  • błona płodowasac in which foetus develops — see also amnion
  • błona jajowasac in which foetus develops — see also amnion
Portuguese saco amniótico, bolsa amniótica
  • saco amnióticosac in which foetus develops — see also amnion
  • bolsa amnióticasac in which foetus develops — see also amnion
Romanian sac amniotic
  • sac amnioticsac in which foetus develops — see also amnion
Russian пло́дный пузы́рь
  • пло́дный пузы́рь (plódnyj puzýrʹ)sac in which foetus develops — see also amnion
Spanish saco amniótico
  • saco amnióticosac in which foetus develops — see also amnion
Swedish fosterhinna
  • fosterhinnasac in which foetus develops — see also amnion
Turkish amniyon kesesi
  • amniyon kesesisac in which foetus develops — see also amnion
Cite this entry
APA

amniotic sac. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/amniotic%20sac

MLA

“amniotic sac.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/amniotic%20sac. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “amniotic sac,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/amniotic%20sac.

Source: amniotic sac on Wiktionary, CC BY-SA 4.0.