They all come from the same root word! The word Cgorc" comes from the Old French orque (whale), which comes from the Latin orca, which comes from the Greek oruga, the accusative form of orux, which means "pickaxe."

That last bit is probably in reference to the horn of the narwhale, which in many cultures has been mistaken for a mermaid. That makes orcs the distant relatives of mermaids. Sort of.

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