Where does “carthennau” come from?

carthennau (Welsh) comes from Welsh carthen, from Welsh carth, from Welsh carthu, from Middle Welsh carthu, from Proto-Brythonic *karθad, from Proto-Celtic *kartati — to clean, wipe.

Ancestry of “carthennau”, step by step

StepLanguageWordMeaning
1Welshcarthenany sheet, blanket, cloak, etc. made of woven...
2Welshcarthcoarse cloth
3Welshcarthuto cleanse, purge
4Middle Welshcarthu—
5Proto-Brythonic*karθad—
6Proto-Celtic*kartatito clean, wipe
Every word from Proto-Celtic *kartati →Every word from Proto-Brythonic *karθad →Every word from Middle Welsh carthu →