Where does “déisden” come from?

déisden (Middle Irish) comes from Old Irish détsin, from Old Irish dét, from Proto-Celtic *dant, from Proto-Indo-European h₃dónts, from Proto-Indo-European h₁ed- — to eat.

Ancestry of “déisden”, step by step

StepLanguageWordMeaning
1Old Irishdétsin—
2Old Irishdéttooth; set of teeth; of ivory
3Proto-Celtic*danttooth
4Proto-Indo-Europeanh₃dóntstooth
5Proto-Indo-Europeanh₁ed-to eat
Every word from Proto-Indo-European h₁ed- →Every word from Proto-Indo-European h₃dónts →Every word from Proto-Celtic *dant →