coast

to roll or move along with little or no effort. We just coasted along on the flat prairie. We coasted along until we came to the bottom of the hill.

There is no visible danger. I'm going to stay hidden here until the coast is clear. You can come out of your hiding place now. The coast is clear.

from the Atlantic to the Pacific Oceans (in the continental U.S.A.); all the land between the Atlantic and Pacific Oceans (considered in either direction). My voice was once heard on a coast-to-coast radio broadcast. Our car made the coast-to-coast trip in eighty hours.

everywhere or all across a country Winter storms are making life difficult from coast to coast.

from one side of a country to the other We travelled across America coast to coast.

if the coast is clear, you can do something or go somewhere because there is no one near who might see or hear you You can come out now, the coast is clear. I waited outside the house until the coast was clear, then softly tapped on the window.

No observers or authorities are present; one can proceed safely. For example, Let's make sure the coast is clear before we set up this surprise party. This expression may have originated among pirates and smugglers who were referring to the absence of coast guards, or with regard to a coastal military invasion, but no citations bear out these theories. By the late 1500s the term was used purely figuratively.