分隔号
分界面
分界线

[ noun ]
a punctuation mark (/) used to separate related items of information
<noun.communication>

Separatrix \Sep`a*ra"trix\, n.; pl. L. {-trices}, E. {-trixes}.
[L., she that separates.] (Arith.)
The decimal point; the dot placed at the left of a decimal
fraction, to separate it from the whole number which it
follows. The term is sometimes also applied to other marks of
separation.