- a mostly inland water route, partly natural and partly artificial, extending 1,550 miles (2,500 km) along the Atlantic coast from Boston to Florida Bay (Atlantic Intracoastal Waterway ) and 1,116 miles (1,800 km) along the Gulf coast from Carrabelle, Florida, to Brownsville, Texas (Gulf Intracoastal Waterway ): constructed to protect small craft from the hazards of the open sea.
- short for Atlantic Intracoastal Waterway
