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an·trum

(ăntrəm)

n. pl. an·tra(ăntrə)

1. A cavity or chamber, especially one in a bone.

2. Either of the sinuses in the bones of the upper jaw, opening into the nasal cavity.

[Late Latin, cavity in the body, from Latin, cave, from Greek antron, back-formed singular from plural antra, possibly originally a collective of earlier *antēr, cave, of unknown origin; possibly akin to Armenian ayr, cave, also from earlier *antēr.]

antral adj.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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