Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Luxembourgish
flaach
←
Proto-Germanic
*flakaz
(derived)
←
Old High German
flah
(derived)
→
Luxembourgish
Fläch
(mention)