Where does “Duck” come from?

Duck derives from Middle English doke, from Old English duce, from Proto-Germanic dukkǭ, from Proto-Germanic dūkaną.

Ancestry of “Duck”, step by step

Step	Language	Word	Meaning
1	Dutch	doek	cloth, linen, fabric; a piece of cloth; screen,...
2	Middle Dutch	doec	cloth
3	Old Dutch	duok	—
4	Proto-West Germanic	dōk	—
5	Proto-Germanic	dōkaz	cloth, rag
6	Proto-Indo-European	dwōg-	—