n. pl. ster·nums or ster·na (-nə)
1. A long flat bone in most vertebrates that is situated along the ventral midline of the thorax and articulates with the ribs. The manubrium of the sternum articulates with the clavicles in humans and certain other vertebrates. Also called breastbone.
2. The ventral portion of a body segment of an arthropod.
[New Latin, from Greek sternon, breast, breastbone; see ster-2 in the Appendix of Indo-European roots.]
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