1. The act of distributing things into classes or categories of the same type
   "The scientist's classification of species was groundbreaking";
   - categorization, categorisation [Brit], compartmentalization, compartmentalisation [Brit], assortment
    
2. A group of people or things arranged by class or category
   "The library used a detailed classification system for organizing books";
   - categorization, categorisation [Brit]
    
3. The basic cognitive process of arranging into classes or categories
   "The librarian's classification of books made them easy to find";
   - categorization, categorisation [Brit], sorting
    
4. Restriction imposed by the government on documents or weapons that are available only to certain authorized people
   "The document's classification prevented its public release"

Derived forms: classifications

Type of: arrangement, basic cognitive process, confinement, grouping, restriction

Antonym: declassification

Encyclopedia: Classification