From Longman Dictionary of Contemporary Englishredactionre‧dac‧tion /rɪˈdækʃən/ noun [countable, uncountable] the action of changing, removing, or putting black marks over parts of an official document before it is published in order to keep information secret There were complaints about the redaction of details of MPs’ expenses claims. —redact /rɪˈdækt/ verb [transitive]