Etymograph

English

isoeffective

Isoeffective comes from French effectif ‘number of members of a group’, from Latin effectīvus ‘creative’, and ultimately from Proto-Indo-European *dʰeh₁k-.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*dʰeh₁k-1reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*dʰh₁kyéti1reconstructed
  3. Proto-Italicc. 1500–700 BCE*θakjō1reconstructed
  4. Proto-Italicc. 1500–700 BCE*fakjō1‘to make’reconstructed
  5. Latinc. 75 BCE–200 CEfaciō1‘to make, construct, fashion, frame, build, erect’
  6. Latinc. 75 BCE–200 CEefficiō1‘to make out or work out’
  7. Latinc. 75 BCE–200 CEeffectīvus1‘creative’
  8. Frenchc. 1600–presenteffectif1‘number of members of a group’
  9. English1500–presenteffective1
  10. Englishtodayisoeffective1

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, English isoeffective

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*dʰeh₁k-Wiktionary, English isoeffectivereconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*dʰh₁kyétiWiktionary, English isoeffectivereconstructed
  3. Proto-Italicc. 1500–700 BCE*θakjōWiktionary, English isoeffectivereconstructed
  4. Proto-Italicc. 1500–700 BCE*fakjōWiktionary, English isoeffective‘to make’reconstructed
  5. Latinc. 75 BCE–200 CEfaciōWiktionary, English isoeffective‘to make, construct, fashion, frame, build, erect’
  6. Latinc. 75 BCE–200 CEefficiōWiktionary, English isoeffective‘to make out or work out’
  7. Latinc. 75 BCE–200 CEeffectīvusWiktionary, English isoeffective‘creative’
  8. Frenchc. 1600–presenteffectifWiktionary, English isoeffective‘number of members of a group’
  9. English1500–presenteffectiveWiktionary, English isoeffective
  10. EnglishtodayisoeffectiveWiktionary, English isoeffective

A compound of iso- + effective

Ancient Greek ἴσος ‘equal’

English iso-

Latin efficiō ‘to make; bring about’

Latin effectīvus ‘productive; effective’

French effectif ‘effective’

English effective

Linked words

through Proto-Italic *θakjō

affectionate, imperfection, putrefaction, 62 more

through Proto-Italic *fakjō ‘to make’

factor, difficulty, interface, manufacture, perfection, faction, affection, facet, imperfect, defection, deface, affective, defector, confectionary, affectation, 65 more

through Latin faciō ‘to make, construct, fashion, frame, build, erect’

face, fact, difficult, perfect, profit, feature, facility, faculty, sacrifice, affair, facial, facilitate, affect, deficit, infection, feat, superficial, facade, counterfeit, deficient, fetish, defect, facsimile, infect, hacienda, maleficent, aficionado, parfait, facies, beautify, difficile, confit, beneficent, confection, effector, refectory, 80 more

through Latin efficiō ‘to make out or work out’

effect, efficient, efficacy, efficacious, 14 more

through English effective

effectively, effectiveness, ineffective, 10 more

Today it means

adj Of a dose of radiation: Having the same biological effect.

Sources

Sources: Wiktionary, “isoeffective”. 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 *dʰeh₁k- / isoeffective

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