1. (noun) a system for classifying things

• abo blood group system
• abo group
• abo system
• decimal system of classification
• dewey decimal classification
• dewey decimal system
• file system
• filing system
• grouping
• pigeonholing
• hierarchical classification system
• rating system
• scoring system

1. (noun) a system for classifying things

• arrangement
• organisation
• organization
• system