noun
Common
os
os
Os (noun) means In anatomy, a bone, or an opening shaped like a mouth — most commonly the opening at either end of the cervix. Example: “The doctor checked the dilation of the cervical os during labour.”
noun
1
In anatomy, a bone, or an opening shaped like a mouth — most commonly the opening at either end of the cervix.
"The doctor checked the dilation of the cervical os during labour."
"The external os had begun to widen slightly."
2
In geology, a long, winding ridge of sand and gravel left behind by a melting glacier (an esker).
"The road follows a long os that winds between two quiet lakes."
"Geologists explained that the os formed when a stream of meltwater once ran beneath the ice."
"Hikers followed the crest of the os for miles across the old glacial plain."
How to use os
Learner’s notesIn plain EnglishA technical term, mainly used in medicine for a bodily opening (especially the cervix) and in geology for a ridge of glacial debris.
Common mistake
Almost never used outside anatomy or geology textbooks — not a general word for "bone" in everyday English.
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Word forms
- Plural
- ossa, ora, osar
Fill the gap
Can you complete this real example?
The doctor checked the dilation of the cervical _____ during labour.
Etymology
Borrowed directly from Latin os, meaning "bone."
Related words
Frequently asked questions
What does “os” mean?
The word “os” means in anatomy, a bone, or an opening shaped like a mouth — most commonly the opening at either end of the cervix. In plain terms, a technical term, mainly used in medicine for a bodily opening (especially the cervix) and in geology for a ridge of glacial debris.
How do you pronounce “os”?
“Os” is pronounced os (/ɑs/ in IPA).
How do you use “os” in a sentence?
Here is “os” used in a sentence: “The doctor checked the dilation of the cervical os during labour.”
What part of speech is “os”?
“Os” is a noun.
Where does the word “os” come from?
The word “os” comes from Latin. Borrowed directly from Latin os, meaning "bone.".
Is “os” a common word?
“Os” is a fairly common word in modern English.
How many meanings does “os” have?
“Os” has 2 distinct senses listed in this dictionary. The most common is: in anatomy, a bone, or an opening shaped like a mouth — most commonly the opening at either end of the cervix.
What is the difference between os in anatomy and os in geology?
In anatomy, os means a bone or a mouth-shaped opening, most often the opening at either end of the cervix. In geology, os is an entirely separate term for a long, winding ridge of sand and gravel left behind by a melting glacier.
Is os the same as an esker?
Yes. In geology, os is another name for an esker, the long, winding ridge of sand and gravel deposited by a melting glacier. The two words describe the same landform.
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