Where does “Tamisa” come from?

Tamisa (Romanian) comes from French tamise, from Old French Tamise, from Proto-Celtic tamesās, from Proto-Celtic tames, from Proto-Indo-European tm̥Hes-, from Proto-Indo-European témHes-, from Proto-Indo-European temH- — dark.

Ancestry of “Tamisa”, step by step

StepLanguageWordMeaning
1Frenchtamisefirst-person singular present indicative of...
2Old FrenchTamiseThames (river through London)
3Proto-Celtictamesāsriver, waters
4Proto-Celtictames—
5Proto-Indo-Europeantm̥Hes-—
6Proto-Indo-EuropeantémHes-—
7Proto-Indo-EuropeantemH-dark
Every word from Proto-Indo-European temH- →Every word from Proto-Indo-European témHes- →Every word from Proto-Indo-European tm̥Hes- →