Where does “tigiu” come from?

tigiu (Old Irish) comes from Old Irish tiug, from Proto-Celtic tegus, from Proto-Indo-European tégus, from Proto-Indo-European teg-.

Ancestry of “tigiu”, step by step

StepLanguageWordMeaning
1Old Irishtiugthick
2Proto-Celtictegusthick
3Proto-Indo-Europeantégusthick
4Proto-Indo-Europeanteg-—
Every word from Proto-Indo-European teg- →Every word from Proto-Indo-European tégus →Every word from Proto-Celtic tegus →