letters secretglossary / LETTERS SECRET letters secret. Hist. A governmental document that is issued to a private person, closed and sealed, and thus not made available for public inspection. — Also termed letters close. Cf. LETTERS PATENT(1). 词条贡献者 双语律师Natalie,毕业于法国一流的高级翻译学院,擅长翻译各类与监管与政府事务相关的法律文件。