bone
The French word for bone is "os". It is used in the same way as the English word, to refer to the hard, calcified tissue that makes up the skeleton of vertebrate animals. For example, one might say "Je me suis cassé l'os" to mean "I broke my bone".
It is a bone of contention.
This phrase is used to represent a main issue that people disagree about in an argument. In this context, an 'os de contention' is a metaphorical bone that dogs might fight over, used to represent a disputed issue or item.
There is no problem.
This is a colloquial expression used in French to indicate that there is no problem or no difficulty with something. It conveys a sense of easiness and lack of obstacles.
I have a bone to pick with you.
This is an informal way to tell someone that you are upset with them about something and that you want to discuss it. It implies that the speaker has been harboring resentment or a complaint that needs to be addressed.