More definitions of OSDefinition of OS in:
- The British & World English dictionary
noun (plural ossa /ˈäsə/)Anatomy
- A bone (used chiefly in Latin names of individual bones, e.g., os trapezium).More example sentences
- In this group, the cortex of the os sacrum was destroyed and had a spongelike rather than compact appearance.
- Besides this unambiguous distinguishing character, a second, derived character, exists which is particular to the Carnivora: in the wrist the joint bones, scaphoid, lunate, and os centrale, are fused.
noun (plural ora /ˈōrə/)Anatomy
- An opening or entrance to a passage, especially one at either end of the cervix of the uterus.More example sentences
- The distance between the internal and external os was measured both as a straight line and also as a curved line along the endocervical canal.
- The internal os closes by 3 days, the external os by 3 weeks.
mid 18th century: from Latin os 'mouth'.