Mason-Dix‧on Line, the /ˌmeɪsən ˈdɪksən laɪn/
the border between the states of Maryland and Pennsylvania in the US. It is known for dividing the states of the South where it was legal to own slaves from the states of the North where it was illegal, until the end of the American Civil War. Some people still consider it to be a dividing line between the North and South of the US.

[TahlilGaran] Dictionary of Contemporary English ▲