Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Scottish Gaelic
sùgh
←
Proto-Celtic
*sūgos
(inherited)
←
Latin
sūcus
(cognate)
←
Old Irish
súg
(inherited)
→
Irish
sú
(cognate)