Definition & Meaning of "(the|that) ship has (long|) sailed"

What is the origin of the idiom "the ship has sailed" and when to use it?

The phrase "the ship has sailed" is an idiom used to convey that an opportunity or a chance for a particular action or event has passed, and it is no longer feasible or relevant. The origin of this phrase relates to the idea that once a ship has departed from a harbor, it becomes increasingly difficult or impossible to catch up to it.