shipping lane
From Longman Dictionary of Contemporary EnglishRelated topics: Watershipping laneˈshipping ˌlane noun [countable] TTWan officially approved path of travel that ships must followExamples from the Corpusshipping lane• We trudged across the main shipping lane with tankers and coasters hooting irritably at us to get out of the way.• The moment we were across the shipping lane, we dropped the tow.