• Classification systems by subject (36 C, 32 P)

A

• Aarne-Thompson grouping (25 C, 9 P)
• Aircraft categories (8 P)

D

• Decimal classification systems (5 P)

E

• Educational classification systems (11 P)

I

• Identifiers (20 C, 183 P)
• International classification systems (1 C, 8 P)
• Internet self-classification codes (3 P)

L

• Library cataloging and classification (5 C, 155 P)

R

• Rating systems (13 C, 44 P)

S

• Scales (10 C, 39 P)
• Stock market indices (8 C, 13 P)

T

• Taxonomy (6 C, 25 P)
• Types of groupings (2 C, 17 P)

• Classification
• Rating

A

• Aarne–Thompson–Uther Index
• ACM Computing Classification System
• Andre Walker Hair Typing System
• Animal as Bridegroom
• ATT&CK

B

• Breast cancer classification
• Buddhist Doctrinal Classification

C

• Celestial Emporium of Benevolent Knowledge
• Characteristica universalis
• Classification chart
• Classification of advocacy groups
• Classification of Built Heritage in Portugal
• Classification of European Inland Waterways
• Classification of the Functions of Government
• Classification of Types of Construction
• Classification scheme (information science)
• Common Attack Pattern Enumeration and Classification
• Common Weakness Enumeration
• Crime Classification Manual

D

• Dana classification system
• Data classification (data management)
• Dewey Decimal Classification
• Diairesis

F

• Fire classification

G

• Groves classification system

H

• Historical Thesaurus of English
• Hornbostel–Sachs

I

• Information Coding Classification

L

• Lonclass

M

• McGuire's Motivations
• Memex
• Merchant category code
• Meteorite classification
• Motif-Index of Folk-Literature
• Multiple-alarm fire
• Mundaneum

O

• Operational taxonomic unit

P

• PANOSE

R

• Resin identification code
• Roget's Thesaurus

T

• The Three Golden Children (folklore)
• Trichotomy (philosophy)
• Typology

U

• UNESCO nomenclature