Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*oxtū
→
Breton
eizh
(inherited)
→
Welsh
wyth
(inherited)
→
Irish
ocht
(inherited)
→
Scottish Gaelic
ochd
(inherited)
→
Manx
hoght
(inherited)
→
Cornish
eth
(inherited)
→
Old Irish
ocht
(inherited)