Most of the dictionaries agree that we Americans got the name cranberry from the Low German kraanbere, “crane berry,” from the fact that the plant flourishes in marshy lands frequented by cranes.
But Dr. Mathews, in Dictionary of Americanisms, questions this assumption.
The name, he points out, was used by John Eliot in Day-breaking, written in 1647.
He doubts that the Low German word would have penetrated to eastern Massachusetts at that early date, and thinks it more likely that our word was already in dialectal English use.