ecotourism

The story

1. Proto-Indo-European*weyḱ-
2. Proto-Indo-European*wóyḱos
3. Proto-Hellenic*wóikos
4. Ancient Greekϝοῖκος (woîkos)
5. Ancient Greekοἶκος (oîkos)
6. Latinoeco-
7. Frenchéco-
8. Englisheco-
9. Proto-Indo-European*terh₁-
10. Proto-Indo-European*tórh₁nos
11. Proto-Hellenic*tórnos
12. Ancient Greekτόρνος (tórnos)
13. Latintornus
14. Latintornō
15. Old Frenchtorner
16. Old Frenchtour
17. Englishtour
18. Englishtourism
19. English todayecotourism

From eco- + tourism.