a bone of contention
something that two or more people argue about fiercely over a long period of time

[TahlilGaran] Advanced Learner's Dictionary ▲

bone of contention
a matter of disagreement.
Legal costs have continued to be a bone of contention between the two groups.

[TahlilGaran] English Idioms Dictionary ▲

bone of contention
a reason for quarrels, the subject or reason for a fight/dispute
The family cottage was a major bone of contention after the father died.

The size of the project was a bone of contention during the talks between the city and the developer.

[TahlilGaran] English Idioms Dictionary ▲

bone of contention
n. phr. Something to fight over; a reason for quarrels; the subject of a fight.
The boundary line between the farms was a bone of contention between the two farmers.
The use of the car was a bone of contention between Joe and his wife.

[TahlilGaran] English Idioms Dictionary ▲