Where does “каручка” come from?

каручка (Bulgarian) comes from Bulgarian каруца, from Romanian căruță, from Latin carrūca, from Latin carrus, from Gaulish karros, from Proto-Celtic karros, from Proto-Indo-European ḱr̥sós, from Proto-Indo-European ḱers- — to run.

Ancestry of “каручка”, step by step

Step	Language	Word	Meaning
1	Bulgarian	каруца	carriage, wagon
2	Romanian	căruță	wagon, small cart, often horse-drawn
3	Latin	carrūca	A chariot
4	Latin	carrus	a wagon, a four-wheeled baggage cart; a cartload,...
5	Gaulish	karros	wagon
6	Proto-Celtic	karros	wagon
7	Proto-Indo-European	ḱr̥sós	vehicle
8	Proto-Indo-European	ḱers-	to run

Every word from Proto-Indo-European ḱers- →Every word from Proto-Indo-European ḱr̥sós →Every word from Proto-Celtic karros →