Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
sechtmain
←
Latin
septimus
(derived)
→
Irish
seachtain
(inherited)
→
Scottish Gaelic
seachdain
(inherited)
→
Manx
shiaghtin
(inherited)