Definition & Meaning of "bone of contention"

What is the origin of the idiom "bone of contention" and when to use it?

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.