Bone of contention

The phrase "bone of contention" refers to a subject or issue that causes disagreement or conflict between individuals or groups. It commonly denotes a topic or matter that is a source of ongoing dispute or tension, with each side holding differing opinions or interests, often resulting in arguments or disagreements. The phrase implies that the contentious issue is similar to a bone that two dogs might fight over, with both parties refusing to let go or resolve the dispute.