Where does “mur” come from?

mur (Middle Breton) comes from Old Breton mur, from Proto-Brythonic *mʉr, from Latin mūrus, from Old Latin moerus, from Proto-Indo-European mēy- — soft, tender, dear.

Ancestry of “mur”, step by step

Step	Language	Word	Meaning
1	Old Breton	mur	—
2	Proto-Brythonic	*mʉr	—
3	Latin	mūrus	wall, city wall(s), (usually of a city, as opposed to pariēs)
4	Old Latin	moerus	—
5	Proto-Indo-European	mēy-	soft, tender, dear

Words derived from “mur”

Every word from Proto-Indo-European mēy- →Every word from Old Latin moerus →Every word from Latin mūrus →