Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Portuguese
carvão
←
Proto-Indo-European
*ker
(derived)
←
Latin
carbo
(inherited)
←
Portuguese
carbono
(doublet)
←
Old Portuguese
carvon
(inherited)
→
Friulian
cjarbon
(cognate)
→
Friulian
cjarvon
(cognate)
→
Galician
carbón
(cognate)
→
Portuguese
carbono
(doublet)