Where does “flak” come from?

flak (Old Saxon) comes from Proto-Germanic *flak, from Proto-Germanic flakaz, from Proto-Indo-European pl̥keh — flat surface.

Ancestry of “flak”, step by step

StepLanguageWordMeaning
1Proto-Germanic*flak—
2Proto-Germanicflakazflat
3Proto-Indo-Europeanpl̥kehflat surface

Words derived from “flak”

Every word from Proto-Indo-European pl̥keh →Every word from Proto-Germanic flakaz →Every word from Proto-Germanic *flak →