allantois: meaning, definition, pronunciation and examples
C2Technical / Scientific
Quick answer
What does “allantois” mean?
An extra-embryonic membrane in reptiles, birds, and mammals involved in respiration and waste management.
Audio
Pronunciation
Definition
Meaning and Definition
An extra-embryonic membrane in reptiles, birds, and mammals involved in respiration and waste management.
In developmental biology, a sac-like structure arising from the gut of the embryo, crucial for gas exchange and storage of metabolic wastes.
Dialectal Variation
British vs American Usage
Differences
No significant usage differences; spelling and pronunciation are consistent across varieties.
Connotations
Purely technical, devoid of cultural connotations.
Frequency
Extremely low frequency in general discourse, confined to specialised biological texts.
Grammar
How to Use “allantois” in a Sentence
The allantois + verb (develops, fuses, regresses)Noun + of the allantois (development, function, cavity)Vocabulary
Collocations
Examples
Examples of “allantois” in a Sentence
verb
British English
- The membrane begins to allantoise during the third week.
adjective
British English
- The allantoic fluid was sampled for analysis.
American English
- Researchers studied the allantoic circulation.
Usage
Meaning in Context
Business
Never used.
Academic
Used in advanced biological sciences, specifically embryology and comparative anatomy.
Everyday
Virtually never used.
Technical
Core term in descriptive embryology and veterinary science.
Vocabulary
Synonyms of “allantois”
Neutral
Weak
Watch out
Common Mistakes When Using “allantois”
- Mispronouncing the final '-is' as '-us' (e.g., /əˈlæntəʊəs/).
- Using it as an uncountable noun.
- Confusing it with the amnion or chorion.
FAQ
Frequently Asked Questions
Yes, but only transiently in early development. It contributes to the formation of the umbilical cord and urinary bladder.
No, they are distinct extra-embryonic membranes. The yolk sac is involved in early nutrition, while the allantois handles respiration and waste.
It is particularly large and functional in reptiles and birds, where it acts as a major respiratory organ inside the egg.
It is the adjective form, meaning 'pertaining to or derived from the allantois', as in 'allantoic fluid'.
An extra-embryonic membrane in reptiles, birds, and mammals involved in respiration and waste management.
Allantois is usually technical / scientific in register.
Allantois: in British English it is pronounced /əˈlæntəʊɪs/, and in American English it is pronounced /əˈlæntoʊɪs/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think: "ALL ANimals TOuch It Sometimes" – a membrane many vertebrate embryos have.
Conceptual Metaphor
A biological 'waste bag' and 'lung' for the developing embryo.
Practice
Quiz
The allantois is primarily involved in: