what does mean "sea change"?

Question

what does mean "sea change"?
Where come from this word?

Answer 1

sea change is defined as

1. a striking change, as in appearance, often for the better.
2. any major transformation or alteration.
3. a transformation brought about by the sea.

Personally, I would say that definition 1 is the most accurate.

Answer 2

It means when people choose to quit living in large cities to move to smaller coastal communities for a more relaxed lifestyle

Answer 3

america english