bone of contention

a subject over which people disagree

The idiom "bone of contention" has roots in medieval English, where it originated from the literal meaning of a "bone" as an object of dispute or contention between two dogs. The phrase evolved to describe any contentious issue or subject that serves as a cause for disagreement or conflict between individuals or groups. Over time, it transitioned from its literal origins to a metaphorical usage, becoming a common expression in the English language to denote a central point of disagreement or conflict.

The allocation of funds became the bone of contention during the budget meeting, leading to heated debates among department heads.
In the family discussion about holiday plans, the choice of destination became a bone of contention, with each member advocating for a different location.
The issue of resource distribution has been a long-standing bone of contention between the two neighboring countries.
The decision to implement new policies became the bone of contention between the management and the employees, sparking protests in the workplace.
When negotiating the contract, the compensation package emerged as the primary bone of contention, delaying the agreement between the employer and the candidate.