pioneerpioneer

Pioneer comes from Middle French pionnier ‘foot soldier’, from Old French peon ‘foot soldier’, from Late Latin pedō ‘pedestrian’, and ultimately from Proto-Indo-European *ped- ‘to walk’.

1. Proto-Indo-Europeanc. 4500–2500 BCE*ped-¹‘to walk’reconstructed
2. Proto-Indo-Europeanc. 4500–2500 BCE*pṓds²‘foot’reconstructed
3. Proto-Italicc. 1500–700 BCE*pets²‘foot’reconstructed
4. Latinc. 75 BCE–200 CEpēs³‘foot’
5. Late Latinc. 200–600 CEpedō⁴as pedōnem‘pedestrian’
6. Old Frenchc. 842–1400peon⁵‘foot soldier’
7. Old Frenchc. 842–1400peonier⁵‘foot soldier’
8. Middle Frenchc. 1400–1600pionnier⁵‘foot soldier’
9. Englishearliest quotation c. 1587–1588pioneer⁵

1. ¹ Wiktionary, Proto-Indo-European *pṓds
2. ² Wiktionary, Latin pes
3. ³ Wiktionary, Latin pedo
4. ⁴ Wiktionary, Old French peon
5. ⁵ Wiktionary, English pioneer
6. Earliest quotation in Wiktionary’s entry: c. 1587–1588, Christopher Marlowe, Tamburlaine the Great. […] The First Part […]: “[King of] Fess. What thinks your greatnes beſt to…”.