Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
ocht
←
Proto-Celtic
*oxtū
(inherited)
←
Proto-Indo-European
*oḱtṓw
(inherited)
←
Old Irish
ocht
(inherited)
→
English
eight
(cognate)
→
Irish
ochtapas
(mention)
→
Irish
ochtó
(mention)