Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
trec'h
←
Proto-Celtic
*trexsnos
(inherited(sga/br))
←
Proto-Indo-European
*(s)treg-
(derived(sga/br))