[ os-tee-uh m ]
/ ˈɒs ti əm /

noun, plural os·ti·a [os-tee-uh] /ˈɒs ti ə/.

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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ostium

British Dictionary definitions for ostium

/ (ˈɒstɪəm) /

noun plural -tia (-tɪə) biology

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 for ostium

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

Medicine definitions for ostium

[ ŏstē-əm ]

n. pl. os•ti•a (-tē-ə)

A small opening or orifice, as in a body organ.

Other words from ostium

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