bone
/bəʊn/·본·noun
a hard part of the body skeleton
Old EnglishCEFR A2
Root
Proto-Germanic '*bainą' (bone, leg)
Proto-Germanic *bainą → Old English bān → Modern bone. Latin used os/ossis (root of English osseous, ossify) — a separate root.
In a word
English bone came straight from the Germanic branch. For the same meaning Latin used another root, os/ossis — the source of English osseous (of bone), ossify (turn to bone). While the doctor writes "ossify," the patient says "bone." On a single body part, two parallel words grew up: the Latin one for scholarship, the Germanic one for everyday life.
Examples
The dog buried a bone in the yard.
He broke a bone in his arm.
I can feel it in my bones.
Related
bonybackbonebonemealosseousossify