Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Bulgarian
руд
←
Proto-Slavic
*rudъ
(inherited)
←
Proto-Slavic
*rǫdъ
(inherited)
→
Serbo-Croatian
rud
(cognate)
→
Serbo-Croatian
руд
(cognate)