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[os-tee-uh m] /ˈɒs ti əm/
noun, plural ostia
[os-tee-uh] /ˈɒs ti ə/ (Show IPA)
Anatomy, Zoology. a small opening or orifice, as at the end of the oviduct.
Zoology. one of the tiny holes in the body of a sponge.
Origin of ostium
First recorded in 1655-65, ostium is from the Latin word ōstium entrance, river mouth Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for ostium


noun (biology) (pl) -tia (-tɪə)
any of the pores in sponges through which water enters the body
any of the openings in the heart of an arthropod through which blood enters
any similar opening
Word Origin
C17: from Latin: door, entrance
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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ostium in Medicine

ostium os·ti·um (ŏs'tē-əm)
n. pl. os·ti·a (-tē-ə)
A small opening or orifice, as in a body organ.

os'ti·al adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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