Etymograph

English

separatrix

Separatrix comes from Latin separō ‘to divide’, from parō ‘to arrange’, and ultimately from Proto-Indo-European *pr̥h₃o-.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*pr̥h₃o-1reconstructed
  2. Latinc. 75 BCE–200 CE*paro-1reconstructed
  3. Latinc. 75 BCE–200 CEparō1‘to arrange’
  4. Latinc. 75 BCE–200 CEseparō2as sēparāre‘to divide’
  5. Latinc. 75 BCE–200 CEsēparātrīx2
  6. Englishearliest quotation 1660separatrix2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin separo
  2. 2 Wiktionary, English separatrix
  3. Earliest quotation in Wiktionary’s entry: 1660, Jonas Moore, Moor's Arithmetick: “Therefore in writing of decimall parts let the separatrix…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*pr̥h₃o-Wiktionary, Latin separoreconstructed
  2. Latinc. 75 BCE–200 CE*paro-Wiktionary, Latin separoreconstructed
  3. Latinc. 75 BCE–200 CEparōWiktionary, Latin separo‘to arrange’
  4. Latinc. 75 BCE–200 CEseparōWiktionary, English separatrixas sēparāre‘to divide’
  5. Latinc. 75 BCE–200 CEsēparātrīxWiktionary, English separatrix
  6. Englishearliest quotation 1660separatrixWiktionary, English separatrix. Earliest quotation in Wiktionary’s entry: 1660, Jonas Moore, Moor's Arithmetick: “Therefore in writing of decimall parts let the separatrix…”

Equivalent to separate + -trix

Proto-Indo-European *pr̥h₃o-

…

Latin sēparō ‘to divide, separate’

Latin sēparātus ‘divided’

Middle English separat ‘separated’

Middle English separaten ‘to separate’

English separate

The story

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). 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.

Full etymology on Wiktionary

Linked words

through Latin parō ‘to arrange’

empire, emperor, repair, imperial, preparation, empress, apparel, apparatus, parachute, preparatory, disparate, imperium, imperious, pare, rampart, imperator, reparation, 18 more

through Latin separō ‘to divide’

several, severance, inseparable, 4 more

Today it means

noun The ⟨L⟩ or pipe ⟨|⟩ mark formerly used to divide integers from decimals.

Sources

Sources: Wiktionary, “separatrix”; the older steps come from the Wiktionary entry for Latin separo. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Proto-Indo-European *pr̥h₃o- / separatrix

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