Where does “dark flow” come from?

dark flow (English) comes from English dark, from Middle English derk, from Old English deorc, from Proto-West Germanic derk, from Proto-Germanic derkaz, from Proto-Indo-European dʰerg-o-s, from Proto-Indo-European dʰerg-, from Proto-Indo-European dʰer- — to support; to hold.

dark flow (English): A possible non-random component of the peculiar velocity of galaxy clusters

Definitions

  1. A possible non-random component of the peculiar velocity of galaxy clusters

Ancestry of “dark flow”, step by step

dark flow traces back through two separate lines of ancestry.

via English dark

StepLanguageWordMeaning
1EnglishdarkHaving an absolute or relative lack of light;...
2Middle Englishderkdark
3Old Englishdeorcdark
4Proto-West Germanicderkdirty; dark
5Proto-Germanicderkaz
6Proto-Indo-Europeandʰerg-o-s
7Proto-Indo-Europeandʰerg-to dim, darken; dim, dull; dark, dusky
8Proto-Indo-Europeandʰer-to support; to hold

via English flow

StepLanguageWordMeaning
1EnglishflowA movement in people or things with a particular...
2Middle EnglishflowenTo flow, stream, or issue; to move; To become...
3Old Englishflōwanto flow
4Proto-West Germanic*flōanto flow
5Proto-Germanicflōanąto flow
6Proto-Indo-Europeanplōw-to flow, swim; to pour, wash
7Proto-Indo-Europeanplew-to fly, flow, run
Every word from Proto-Indo-European dʰer-Every word from Proto-Indo-European dʰerg-Every word from Proto-Indo-European dʰerg-o-s