Also found in: Thesaurus, Encyclopedia, Wikipedia.
The original line extended from the southeast corner of the colony of Pennsylvania 233 miles west and 82 miles south.
A line marking the boundary between the colonies of Pennsylvania and Maryland, established between 1763 and 1767 by the British surveyors Charles Mason (1730-1787) and Jeremiah Dixon (1733-1779). It was regarded as the division between free and slave states before the Civil War.
Mason-Dixon Line(ˈmeɪsə n ˈdɪksən) or
Mason and Dixon Line
(Human Geography) the state boundary between Maryland and Pennsylvania: surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon; popularly regarded as the dividing line between North and South, esp between the free and the slave states before the American Civil War
or Ma′son and Dix′on line`,
the boundary between Pennsylvania and Maryland surveyed (1763–67) by Charles Mason and Jeremiah Dixon, regarded as separating North from South.