Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Gaulish
taruos
←
Proto-Celtic
*tarwos
(inherited)
←
Proto-Indo-European
*táwros
(derived)
←
Old Irish
tarb
(cognate)
→
Irish
tarbh
(cognate)
→
Scottish Gaelic
tarbh
(cognate)
→
Manx
tarroo
(cognate)
→
Old Irish
tarb
(cognate)