1coast 
/ˈkoʊst/ noun
plural coasts /ˈkoʊst/ noun 1 : the land along or near a sea or ocean [count] ▪ sea/rocky coasts [=shores] ▪ the west/east coast ▪ He lives on the coast. [noncount] ▪ We drove along a long stretch of coast. [=shore] 2 the Coast US, informal : the area along or near the Pacific Ocean
▪ He's flying out to the Coast tomorrow.
▪ He's flying out to the Coast tomorrow.
from coast to coast
: from one coast to the other coast of a country or continent
▪ They traveled from coast to coast across the U.S. ▪ The space shuttle launch was on television stations from coast to coast. [=throughout the country] — see also coast-to-coast
▪ They traveled from coast to coast across the U.S. ▪ The space shuttle launch was on television stations from coast to coast. [=throughout the country] — see also coast-to-coast
the coast is clear
◊When the coast is clear you can go somewhere or do something without being caught or seen because no one is in the area.
▪ OK, the coast is clear—you can come out now!
▪ OK, the coast is clear—you can come out now!
— coast·al /ˈkhoʊstl̟/ adjective
▪ coastal areas/regions/waters ▪ coastal mountains
/ˈkhoʊstl̟/ adjective ▪ coastal areas/regions/waters ▪ coastal mountains
