Where does “costrel” come from?

costrel (Middle English) comes from Old French costerel, from Old French costeret, from Latin costa, from Proto-Indo-European kost-.

Ancestry of “costrel”, step by step

Step	Language	Word	Meaning
1	Old French	costerel	—
2	Old French	costeret	—
3	Latin	costa	a rib; a side, a wall
4	Proto-Indo-European	kost-	—

costrel — Etymology, Origin & Word History | Etymology Explorer