What is "Maerin"

According to Barbara Walker’s The Woman’s Encyclopedia of Myths and Secrets,  Maerin is the ancient word for mermaid. Today’s popular mermaid claims a  long and distinguished ancestry dating back to the fish tailed gods and  goddesses worshipped by some of the earliest recorded  civilization.Supremely glamorous, forever combing their hair, just  beyond reach, the elusively desirable mermaid offers the adventurous the  challenge of the unknown and the promise of the wild, forbidden  pleasures of the deep.1  What better name for a cottage by the sea?