Øresund (örəsŭnd´) or the Sound, Swed. Öresund, c.45 mi (70 km) long, strait between the Danish island of Sjælland and Sweden, connecting the Kattegat with the Baltic Sea, to which it is the deepest channel. Between Helsingborg and Helsingør it is only 2.5 mi (4 km) wide. Copenhagen and Malmö are on the Øresund. A strategic passage, control of the strait was long contested between Denmark and Sweden. A bridge-tunnel link across the strait, connecting Copenhagen and Malmö, opened in 2000.
"Øresund." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (September 19, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/oresund
"Øresund." The Columbia Encyclopedia, 6th ed.. . Retrieved September 19, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/oresund