ostium

[os-tee-uhm]

noun

plural

ostia 

1. Anatomy, Zoology.,  a small opening or orifice, as at the end of the oviduct.

2. Zoology.,  one of the tiny holes in the body of a sponge.

ostium

/ ˈɒstɪəm /

noun

1. any of the pores in sponges through which water enters the body

2. any of the openings in the heart of an arthropod through which blood enters

3. any similar opening

Word History and Origins

Origin of ostium¹

First recorded in 1655–65, ostium is from the Latin word ōstium entrance, river mouth

Word History and Origins

Origin of ostium¹

C17: from Latin: door, entrance

Example Sentences

This has nothing to do with the foramen ovale, which occurs as an independent perforation higher up, and at first is known as the ostium secundum.

From Project Gutenberg

At first it does not quite reach the endocardial cushions in the auricular canal, already mentioned, but leaves a gap, called the ostium primum, between.

From Project Gutenberg

When it is established the septum primum grows down and meets the endocardial cushions, and so the ostium primum is obliterated.

From Project Gutenberg

Quid ad hominem claustra, carcer, custodia? liberum ostium habet.

From Project Gutenberg

Decimo quarto Kalendas Januarii Patagonicis recognitis litoribus ad ostium appulit freti.

From Project Gutenberg