From Longman Dictionary of Contemporary Englishdecommissionde‧com‧miss‧ion /ˌdiːkəˈmɪʃən/ verb [transitive] PMWTPto stop using a ship, weapon, or nuclear reactor and to take it to pieces→ See Verb tableFrom Longman Business Dictionarydecommissionde‧com‧mis‧sion /ˌdiːkəˈmɪʃən/ verb [transitive] to destroy a factory, POWER STATION, or other industrial building that has closed down, and to remove anything from it that might be harmful or dangerous25 of the mine’s 260 full-time employees will be kept on to decommission the property.The two nuclear power plants are due to be decommissioned in 2045. —decommission noun [countable, uncountable]the decommission of oil refineries→ See Verb table