Antrum
Pronunciation : An"trum
Part of Speech : n.; pl. Antra.
Etymology : [L., fr. Gr.
Definition : Defn: A cavern or cavity, esp. an anatomical cavity or sinus. Huxley.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder