That's the problem with the lack of macrons and apices, here.
ōs = mouth,. (as in "per os"), gave oral from its genitive oris.
And also, second meanings: "face", "facial expression",
And also: voice, word, language, tongue, pronunciation, tongue
For bones, there are two words ŏs, neuter (genitive: Ossis, plural accu ossa) And ossum (genitive: Ossī, plural accu. ossa): neuter.
Second meanings: entrails, stone of fruit/the hard part of something, Sobriety. Skinniness.
Ossă = feminine. A Thessalia mountain.
It's the reason why macrons and apices become optional once you are not a beginner anymore, but are crucial to beginners.
If you pronounce "os" and "os" the same, you are wrong.
I agree with you about the desirability of including macrons, PN. However: 1) the English antonym of "macron" is not "apex" but "breve"; and 2) there is no need to use breves, since the absence of a macron (where they are used) is -- by default -- an indication of short vowel length. (I refer you to le rasoir d'Ockham.)
When my children were young (c 1970) they had a rota after the evening meal. One - clear the table; two - wash the dishes; three - dry the dishes; four - put dried dishes etc in correct places. If the child doing duty two couldn't reach the sink, there was a wooden box to stand on. On each side of it the words: "Boneless Chicken". As the duty washer climbed onto the box, the others danced around the kitchen with floppy limbs, clucking like chickens. Of course the cans that once filled the box had contained boned, cooked chicken. I hope the peacocks in the Roman market were sold ready plucked. For many today the idea of a family sitting around a table, eating the same food and with neither mobile phones nor baseball caps, is as alien as buying peacock meat in a market.
As said by Mosfet (I saw it later)
It can be the (nominative) word Ossum,
The (nominative) word Os
As they have both their acc. plural in "Ossa".
Os is a popular variant, and gave directly the French "os". (bone/bones).
I think French is not the closest language from Latin, but maybe one of the closest from popular Latin, or vulgar Latin.
When the Spanish and the Italian seems rather from Ossum (Spanish: hueso), (Italian: Osso)