The story
- Proto-Indo-European*kʷetwóres
- Proto-Hellenic*kʷétwores
- Ancient Greekτέσσᾰρες (téssăres)
- Ancient Greekτετρᾰ- (tetră-)
- Englishtetra-
- Englishhydro
- Englishtetrahydro
- Englishgestrinone
- English todaytetrahydrogestrinone
From tetrahydro + gestrinone.
Etymology from Wiktionary, CC BY-SA 4.0.