Estonian Cod Salad & Horseradish Sauce

This salad, called "Tursasalat ja Mädarõikakaste" in Estonian,* is great on its own with some rye bread, or it can certainly be used as an appetizer or as an accompaniment to a main dish. I adapted my recipe from a recipe in, "The Food and Cooking of Estonia, Latvia and Lithuania," by Silvena Johan Lauta with photography by Martin Brigdale, published by Aquamarine, a division of Anness Publishing Ltd, London, 2009.  

Ingredients:

1 1/2 pounds cod fillets, poached in salted water
2 tablespoons lemon juice
3 tablespoons horseradish
2/3 cup sour cream
3 tablespoons mayonnaise
1/4 cup finely chopped onion
1/4 cup peeled chopped cucumber
1/2 cup arugula 
3 tablespoons chopped dill
1/2 teaspoon black pepper
1 teaspoon salt 

Poach the cod in salted water until it can be flaked. Drain the fish well, flake the fish, then sprinkle on the lemon juice. In a bowl, mix together the other ingredients, then gently fold in the flaked cod.

* Estonian is a language from the Uralic family of languages and it is closely related to Finnish, and somewhat more distantly to Hungarian. Finland lies just north of Estonia, across the Baltic Sea, or over land to the northeast, where the two countries are separated by part of Russia. The Uralic languages are non Indo European, the ancestor of nearly all other European languages, including among many others, English, German, Swedish, Latvian and Russian.    

WORD HISTORY:
Arugula (Rocket)-First, this word "rocket" is NOT the same word for a type of missile, and they have totally different sources. This plant name word goes back to Indo European "ghers/gher" meaning, "to bristle," and an extended form "gherukah." This gave Latin "eruca," meaning "caterpillar" (apparently, "the bristly insect"), and also the name for a "plant related to cabbage and kale," seemingly from the "bristling leaves." The general plant name passed into the evolving Italian language as "ruka," with the diminutive form being "ruchetta," but in dialectal northern Italian as "arigola." English first borrowed the plant name word as "rocket," from "ruchetta," in the 1500s, but circa 1970 American English took on "arugula" from the dialectal Italian form, "seemingly" from northern Italian immigrants and their culinary use of the plant. In England and other parts of Britain, "rocket" remains the common word for the plant.