The ulna is a long, thin bone in your forearm, on the opposite side of your arm from your thumb.(noun)
An example of ulna is a bone in your forearm.
See ulna in Webster's New World College Dictionary
See ulna in American Heritage Dictionary 4
noun pl. ul·nas or ul·nae (-nē)
Origin: Latin, elbow, forearm; see el- in Indo-European roots.
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