• synonyms


[os-tee-uh m]
noun, plural os·ti·a [os-tee-uh] /ˈɒs ti ə/.
  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.
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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. 2018

Examples from the Web for ostium

Historical Examples of ostium

  • Here in the door-way, or ostium, we stop to note the "Salve!"

    Historic Boys

    Elbridge Streeter Brooks

  • The porter, who sat in a niche of the entrance-corridor (ostium).

  • This will bring the anterior wall of the sinus with its ostium into view.

  • Double doors admitted the visitor to the entrance-hall, or ostium.

  • With the help of cocaine the ostium can then be enlarged with various instruments.

British Dictionary definitions for ostium


noun plural -tia (-tɪə) biology
  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
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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

ostium in Medicine


n. pl. os•ti•a (-tē-ə)
  1. A small opening or orifice, as in a body organ.
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Related formsosti•al adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.