In Roman mythology, Terminus was the god of boundaries. The stones used to mark borders were sacred to him.
On February 23, a festival called Terminalia was celebrated annually by the Romans in his honor. The stone boundary-markers were drenched in sacrificial blood and placed on flowers to renew its protective powers. The stone was later thought of as a god.
Jupiter was worshipped as Jupiter Terminus or Jupiter Terminalus. He fit into the same role as the independent god Terminus.