Where does “tau” come from?

tau (Old Frisian) comes from Proto-Germanic tawwą, from Proto-Indo-European dewh₂- — to fit.

Ancestry of “tau”, step by step

StepLanguageWordMeaning
1Proto-Germanictawwątool; apparatus; gadget; equipment; rigging;...
2Proto-Indo-Europeandewh₂-to fit
Every word from Proto-Indo-European dewh₂- →Every word from Proto-Germanic tawwą →