arranged in classes or categories

a classified catalogue of books

(of information or documents) designated as officially secret and accessible only to authorized people

classified information on nuclear experiments

small advertisements placed in a newspaper and organized in categories

arrange (a group of people or things) in classes or categories according to shared qualities or characteristics

mountain peaks are classified according to their shape

designate (documents or information) as officially secret

government officials classified 6.3 million documents in 1992