Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
llon
←
Proto-Brythonic
*llonn
(inherited)
←
Proto-Celtic
*londos
(inherited)
←
Old Irish
lond
(cognate)
←
Middle Welsh
llonn
(inherited)