Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Icelandic
hjálpa
←
Proto-Germanic
*helpaną
(derived)
←
Proto-Indo-European
*ḱelb-
(derived)
←
Proto-Indo-European
*ḱelp-
(mention)
←
Old Norse
hjalpa
(derived)
→
Icelandic
hjálpari
(suffix)
→
Luxembourgish
hëllefen
(cognate)