Meaning of Mason-Dixon line

Ma'son-Dix'on line"

Pronunciation: (mā'sun-dik'sun), [key]
  1. the boundary between Pennsylvania and Maryland, partly surveyed by Charles Mason and Jeremiah Dixon between 1763 and 1767, popularly considered before the end of slavery as a line of demarcation between free and slave states.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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