The story
- Proto-Indo-European*dóru
- Proto-Germanic*terwą
- Old Englishteoru
- Middle Englishter
- Englishtar
- Proto-Indo-European*pel-
- Latinpallium
- Old Frenchpaile
- Old Englishpæl
- Middle Englishpal
- Englishpall
- English todaytarpaulin
From tar + pall (“heavy canvas”) + -ing. The sailor sense reflects that sailors of centuries past often wore garments made of tarred cloth (for weatherproofing).
Etymology from Wiktionary, CC BY-SA 4.0.