A "relish" is a chopped food item used as a condiment. Cucumber pickles are often used, but so is corn, peaches, pineapple, peppers and mangoe, among others.
Pickles refer to whole or sliced cucumbers that have been pickled. Other pickled foods can include onions, peppers, olives, new corn, watermelon rind, beets and fish.
"Food is our common ground, a universal experience." - James Beard