Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
melen
←
Proto-Brythonic
*melɨn
(inherited)
←
Proto-Celtic
*meli
(derived)
←
Welsh
melyn
(cognate)
→
English
mullein
(cognate)
→
Welsh
melyn
(cognate)
→
French
molène
(cognate)
→
Cornish
melyn
(cognate)