Anat. an opening or orifice
Origin of ostiumClassical Latin ostium: see ostiary
- A small opening or orifice, as in a body organ or passage.
- Any of the small openings or pores in a sponge, through which water is drawn in.
Origin of ostiumLatin &omacron;stium, door, opening, from &omacron;s, mouth; see &omacron;s- in Indo-European roots.