separatrix

plural separatrixes · plural separatrices

1. historicalmediaThe ⟨L⟩ or pipe ⟨|⟩ mark formerly used to divide integers from decimals.

   Therefore in writing of decimall parts let the separatrix be always used.

   1660, Jonas Moore, Moor's Arithmetick, page 13

   Synonyms: pipe, slash

2. obsoletemediaSynonym of decimal point, which replaced such marks.

   Synonyms: decimal point, which replaced such marks

3. mediaThe proofreader's mark resembling a slash ⟨ / ⟩ or vertical bar ⟨ | ⟩ placed after a note in the margin to indicate that it should replace the item(s) struckthrough in the running text or to separate it from other margin notes.
4. A terminator: a line on a partially-illuminated surface separating the lit and shaded regions.
5. natural sciencesThe line between regions having different magnetic fields.
6. mathematicsThe boundary separating two modes of behavior in a differential equation.