the Mason-Dixon Line
noun/ðə ˌmeɪsn ˈdɪksn laɪn/
/ðə ˌmeɪsn ˈdɪksn laɪn/
[singular]- the border between the US states of Maryland and Pennsylvania that is thought of as the dividing line between the south of the US and the north. In the past it formed the northern border of the states that practised slavery.
美国马里兰州和宾夕法尼亚州之间的边界被认为是美国南部和北部之间的分界线。过去，它构成了实行奴隶制的各州的北部边界。