Figuratively, all the waters or oceans of the world. The phrase probably has its origins in Brahmanic mythology: the seven seas dividing and surrounding the seven land masses of the earth. In modern times it has been applied to the seven oceans: Arctic, Antarctic, North and South Atlantic, North and South Pacific, and Indian.
SEVEN SEAS
Meaning of SEVEN SEAS in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012