Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Indo-Portuguese
um
←
Proto-Indo-European
*óynos
(derived)
←
Latin
ūnus
(derived)
←
Portuguese
um
(derived)
←
Old Portuguese
ũu
(derived)