Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Portuguese
escuro
←
Latin
obscūrus
(inherited)
←
Portuguese
obscuro
(doublet)
←
Old Portuguese
escuro
(inherited)
←
Old Portuguese
scuro
(mention)
←
Old Portuguese
oscuro
(mention)
→
Portuguese
obscuro
(doublet)
→
Portuguese
escuridão
(suffix)
→
Portuguese
escurecer
(suffix)