"Cors" (mutated to Gors) is Welsh for "marsh" or "bog", and "goch" is the mutated form of "coch" meaning "red": so the name literally translated means "Red Bog".
In Welsh, "Cors" (which has been mutated to "Gors") means "marsh" or "bog", while "goch" corresponds to the mutated version of "coch," which signifies "red." Thus, the literal translation of the name is "Red Bog."