Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Scottish Gaelic
trom
←
Proto-Celtic
*trummos
(inherited)
←
Welsh
trwm
(cognate)
←
Old Irish
trom
(inherited)
→
Scottish Gaelic
cothrom
(affix)
→
Scottish Gaelic
aotrom
(prefix)