Where does “เดดซี” come from?

เดดซี (Thai) comes from English Dead Sea, from Latin Mare Mortuus.

Ancestry of “เดดซี”, step by step

StepLanguageWordMeaning
1EnglishDead Seanoted for high salinity and for its banks being the lowest land-based elevation on Earth
2LatinMare Mortuus
Every word from Latin Mare MortuusEvery word from English Dead Sea