köken: With irregular stress shift (as in Holunder, lebendig, etc.) from Middle High German forhel, alteration of older forhen, from Old High German forhana, from Proto-Germanic *furhnō, from Proto-Indo-European *perḱ- (“speckled”).
köken: From qızıl (“red”) + ala (“variegated”). Compare Turkmen gyzyl-ala (“motley, multi-colored (with a predominance of red)”), Chagatai قزل الا (qzl ʾlā /qızıl ala/, “trout”), Armeno-Kipchak խըզըլալաճապալըխ (xəzəlalačapaləx, “trout”), and Armenian կարմրախայտ (karmraxayt, “trout”, literally “red-spotted”).
köken: Borrowed from German Forelle, from Proto-Germanic *furhnō. The fish is spotted, hence the name. Compare Sanskrit पृषत् (pṛṣat, “spotted”), Ancient Greek περκνός (perknós), πέρκη (pérkē).
köken: Found in Late Latin. Perhaps from Ancient Greek τρώκτης (trṓktēs, “nibbler”), from τρώγω (trṓgō, “to gnaw”), from Proto-Indo-European *terh₁- (“to rub, to turn”).
köken: From Old Norse aurriði, from aurr (“gravel”) + the verb ríða (“to ride”), meaning something like "one who rides on stones and gravel". Compare Norwegian Nynorsk aure, Swedish öring and Norwegian Bokmål ørret.