Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Norse
Taðkr
←
Irish
Tadhg
(cognate)
←
Old Irish
Tadg
(derived)
→
Irish
Tadhg
(cognate)