separatrix
noun/sɛpəˈɹeɪtɹɪks/
Etymology Learned borrowing from Latin sēparātrīx, the feminine form of separator (originally owing to an implied līnea (“line”)), from sēparāre (“to divide; to separate”) + -trix (forming female agents). By surface analysis, separate + -trix. First developed as a decimal mark among the medieval Arab mathematicians, whence a shorter variant gave rise to the decimal comma employed by many European countries and their former colonies.
Media, Publishing, Typography Historical The ⟨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:
Media, Publishing, Typography Obsolete Synonym of decimal point, which replaced such marks.
Media, Publishing, Typography The 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.
A terminator: a line on a partially-illuminated surface separating the lit and shaded regions.
Natural sciences, Physical sciences, Physics The line between regions having different magnetic fields.
Mathematics, Sciences The boundary separating two modes of behavior in a differential equation.