Hypertext Webster Gateway: "ons"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
Pleurosteon \Pleu*ros"te*on\, n.; pl. L. {Pleurostea}, E.
{-ons}. [NL., fr. Gr. ? a rib + ? a bone.] (Anat.)
The antero-lateral piece which articulates the sternum of
birds.
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