Pronunciation: (stûr'num), [key]
—pl. -naPronunciation: (-nu), [key] -nums.
1. Anat., Zool.a bone or series of bones extending along the middle line of the ventral portion of the body of most vertebrates, consisting in humans of a flat, narrow bone connected with the clavicles and the true ribs; breastbone. See diag. under skeleton.
2. the ventral surface of a body segment of an arthropod.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.