A submarine ridge system extending the length of the Atlantic Ocean from the Arctic to the Antarctic. It is seismically and (in places) volcanically active; the islands of Iceland, the Azores, Ascension, St Helena, and Tristan da Cunha are situated on it.
Definition of Mid-Atlantic Ridge in US English:
Mid-Atlantic Ridge
proper noun
A submarine ridge system that extends the length of the Atlantic Ocean from the Arctic to the Antarctic. It is seismically and (in places) volcanically active; the islands of Iceland, the Azores, Ascension, St. Helena, and Tristan da Cunha are located on it.