the Mason-Dixon Line
noun [ S ] uk/ˌmeɪ.sənˈdɪk.sən ˌlaɪn/ us/ˌmeɪ.sənˈdɪk.sən ˌlaɪn/
梅森-狄克森线（美国马里兰州和宾夕法尼亚州之间的分界线，也是传统上认为的美国北方各州和南方各州的分界线）
the border between the states of Maryland and Pennsylvania in the US, traditionally considered to mark the division between the north and south of the US