Where does “merthyrdod” come from?

merthyrdod (Welsh) comes from Welsh merthyr, from Middle Welsh merthyr, from Proto-Brythonic *merθɨr, from Latin martyr, from Ancient Greek μάρτυρ, from Ancient Greek μάρτυς — witness; martyr.

merthyrdod (Welsh): martyrdom

Definitions

martyrdom

Ancestry of “merthyrdod”, step by step

Step	Language	Word	Meaning
1	Welsh	merthyr	martyr
2	Middle Welsh	merthyr	—
3	Proto-Brythonic	*merθɨr	martyr
4	Latin	martyr	martyr, especially a Christian martyr
5	Ancient Greek	μάρτυρ	Aeolic form of μᾰ́ρτῠς
6	Ancient Greek	μάρτυς	witness; martyr

Every word from Ancient Greek μάρτυς →Every word from Ancient Greek μάρτυρ →Every word from Latin martyr →