The story
- Proto-Indo-European*dwóh₁
- Proto-Indo-European*trísinflu.
- Proto-Indo-European*dwís
- Ancient Greekδιά (diá)
- Ancient Greekδῐᾰ- (dĭă-)
- Proto-Indo-European*med-
- Proto-Indo-European*meh₁-
- Ancient Greekμέτρον (métron)
- Ancient Greekδιάμετρος (diámetros)
- Latindiametros
- Old Frenchdiametre
- English todaydiameter
From Old French diametre (French diamètre), from Latin diametros, from Ancient Greek διάμετρος (diámetros) (γραμμή (grammḗ)) (diametros grammē, “line measuring across”), from διά (diá, “across”) + μέτρον (métron, “measure”). By surface analysis, dia- + -meter.
Etymology from Wiktionary, CC BY-SA 4.0.