noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A small opening or orifice, as in a body organ or passage.
2. 2
   Any of the small openings or pores in a sponge.
3. 3
   The mouth of a river.

Synonyms

All synonyms

canalductintestineporevaginavessel

Etymology

Borrowed from Latin ōstium.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.