Pronunciation: [ˈamnɪˌə͡ʊz] (IPA) 
The word "amnios" refers to the innermost membrane that surrounds the embryo in the womb of mammals. The spelling of this word is derived from its Greek origin, which translates to "lamb skin" due to its thin and delicate texture. It is pronounced as "æmniːɒs" in IPA phonetic transcription. The word is commonly misspelled as "amniotic", which is the adjective form of amnios, used to describe various aspects of fetal development.
Amnios is a noun that refers to the innermost membrane surrounding the embryo of a developing fetus in higher vertebrates. It is also known as the amniotic sac or the amnion, and plays a vital role in protecting and nurturing the developing fetus throughout gestation.
In humans and many other mammals, the amnios is a thin, transparent, fluid-filled sac that develops from the embryonic inner cell mass. This sac encloses the fetus, creating a protective barrier against physical impact, temperature fluctuations, and potential infections. The amniotic fluid within the amnios provides buoyancy, allowing the fetus to move and grow freely, while also cushioning the developing organs and limbs.
The amnios contributes to the development of various fetal structures. For instance, it gives rise to the amniotic cavity, which envelops the entire embryo. As the fetus grows, the amnios expands and adapts to accommodate its increasing size. During childbirth, the amnios ruptures, resulting in the release of amniotic fluid, commonly known as the water breaking.
In summary, the amnios is the inner membrane that encloses and protects the developing fetus during pregnancy. Its fluid-filled sac, known as the amniotic sac, provides a stable and nourishing environment for the fetus, contributing to its healthy growth and development.
In anat., the inner membrane covering the foetus; in bot., the covering of the embryo of the seed.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "amnios" comes from the Greek ἀμνίον (amnion), which means "lamb" or "sheep". It was originally used to refer to the fetal membrane that surrounds and protects the fetus in the womb. The term was derived from the resemblance of this membrane to a thin, delicate layer similar to the skin of a lamb or sheep.
