Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

allantois

play
noun al·lan·to·is \ə-ˈlan-tə-wəs\

Definition of allantois

plural al·lan·to·ides play \ˌa-lən-ˈtō-ə-ˌdēz, ˌa-ˌlan-\

  1. :  a vascular fetal membrane of reptiles, birds, and mammals that is formed as a pouch from the hindgut and that in placental mammals is intimately associated with the chorion in formation of the placenta

al·lan·to·icplay \ˌa-lən-ˈtō-ik, ˌa-ˌlan-\ adjective


Origin of allantois

New Latin, ultimately from Greek allant-, allas sausage


First Known Use: 1646


Medical Dictionary

allantois

play
noun al·lan·to·is \ə-ˈlant-ə-wəs\

Medical Definition of allantois

plural al·lan·to·ides \ˌal-ən-ˈtō-ə-ˌdēz, ˌal-ˌan-\play play

  1. :  a vascular fetal membrane of reptiles, birds, or mammals that is formed as a pouch from the hindgut and that in placental mammals is intimately associated with the chorion in formation of the placenta




Learn More about allantois


Seen and Heard

What made you want to look up allantois? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 10, 2016

to put in good humor

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

duvet kittly-benders spindrift pince-nez
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ