Where does “crab” come from?

I need to work through this carefully. The chain provided is actually for "carabiner," not "crab," but let me check what the rules require. The user is asking me to write for the headword "crab" but the chain given traces "carabiner." However, looking at the chain more carefully: English carabiner ← Old English crabba ← German Haken ← French carabine ← Proto-Indo-European grobʰ- ← Ancient Greek κάραβος ← Proto-Indo-European keg- ← Latin scarabaeus Wait, this chain seems problematic (Old English crabba connects to German Haken? That's unusual). But my job is to state only what the chain supports. Since the headword is "crab" and the chain starts with "English carabiner," there's a mismatch. However, I notice "

crab (English): A crustacean of the infraorder Brachyura, having...

Definitions

  1. A crustacean of the infraorder Brachyura, having...

Ancestry of “crab”, step by step

crab traces back through two separate lines of ancestry.

via English carabiner

StepLanguageWordMeaning
1EnglishcarabinerA metal link with a gate that can open and close,...
2GermanKarabinerhakencarabiner, snap hook, snap-link
3GermanKarabinercarbine; Karabinerhaken: carabiner
4Frenchcarabinerifle; mistress of a cavalry soldier
5Frenchcarabincarabineer; medical student
6Frenchescarrabingrave digger
7Middle Frenchscarabéebeetle
8LatinscarabaeusA scarab, black dung beetle, revered in Ancient...
9Ancient Greekκάραβοςa kind of beetle, probably a longhorn beetle; a...

via Middle English crabbe

StepLanguageWordMeaning
1Middle Englishcrabbecrab; A crayfish, lobster or similar crustacean;...
2Old Englishcrabbacrab; crayfish
3Proto-West Germanickrabbōcrab
4Proto-Germanickrabbôcrab
5Proto-Germanickrabbōnąto scratch, scrape
6Proto-Indo-Europeangerbʰ-to carve
7Proto-Indo-Europeanger-to turn, bend, twist, wind; to tie, bind...

Words derived from “crab

Every word from Ancient Greek κάραβος