Etymograph

English

aptitude

Aptitude comes from Medieval Latin aptitudo ‘aptitude, fitness’, from Latin aptus ‘apt, fit’, and ultimately from Proto-Indo-European *h₂ep-.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂ep-1‘to join, fit (in)’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂ptós1reconstructed
  3. Proto-Italicc. 1500–700 BCE*aptos1reconstructed
  4. Latinc. 75 BCE–200 CEaptus2‘apt, fit’
  5. Medieval Latinc. 600–1500aptitudo2‘aptitude, fitness’
  6. Middle Frenchc. 1400–1600aptitude2
  7. Englishtodayaptitude2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin aptus
  2. 2 Wiktionary, English aptitude

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂ep-Wiktionary, Latin aptus‘to join, fit (in)’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂ptósWiktionary, Latin aptusreconstructed
  3. Proto-Italicc. 1500–700 BCE*aptosWiktionary, Latin aptusreconstructed
  4. Latinc. 75 BCE–200 CEaptusWiktionary, English aptitude‘apt, fit’
  5. Medieval Latinc. 600–1500aptitudoWiktionary, English aptitude‘aptitude, fitness’
  6. Middle Frenchc. 1400–1600aptitudeWiktionary, English aptitude
  7. EnglishtodayaptitudeWiktionary, English aptitude

Linked words

through Proto-Indo-European *h₂ep- ‘to join, fit (in)’

apex, ape, aven, 22 more

through Latin aptus ‘apt, fit’

apt, 11 more

through Medieval Latin aptitudo ‘aptitude, fitness’

attitude, attitudinal, 6 more

Today it means

noun A natural ability to acquire knowledge or skill.

Sources

Sources: Wiktionary, “aptitude”; the older steps come from the Wiktionary entry for Latin aptus. 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 *h₂ep- / aptitude

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