Colon classification

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Colon classification (CC) is a system of library classification developed by Shiyali Ramamrita Ranganathan. It was the first ever faceted (or analytico-synthetic) classification. The first edition was published in 1933.[1] Since then, six more editions have been published. It is especially used in libraries in India.

Its name "colon classification" comes from the use of colons to separate facets in class numbers. However, many other classification schemes, some of which are completely unrelated, also use colons and other punctuation in various functions. Originally, CC used only the colon as a separator, but the second revision onwards use four other punctuation symbols to identify each facet type.

In CC, facets describe "personality" (the most specific subject), matter, energy, space, and time (PMEST). These facets are generally associated with every item in a library, and so form a reasonably universal sorting system.[2]

As an example, the subject "research in the cure of tuberculosis of lungs by x-ray conducted in India in 1950" would be categorized as:


This is summarized in a specific call number:



The colon classification uses 42 main classes that are combined with other letters, numbers and marks in a manner resembling the Library of Congress Classification to sort a publication.


CC uses five primary categories, or facets, to specify the sorting of a publication. Collectively, they are called PMEST:

Indicator Facet
, Personality, the most specific or focal subject
; Matter or property, the substance, properties or materials of the subject.
: Energy, including the processes, operations and activities.
. Space, which relates to the geographic location of the subject.
' Time, which refers to the dates or seasons of the subject.

Other symbols can be used to indicate components of facets called isolates, and to specify complex combinations or relationships between disciplines.


The following are the main classes of CC, with some subclasses, the main method used to sort the subclass using the PMEST scheme and examples showing application of PMEST.

z Generalia
1 Universe of Knowledge
2 Library Science
3 Book science
4 Journalism
A Natural science
B Mathematics
B2 Algebra
C Physics
D Engineering
E Chemistry
F Technology
G Biology
H Geology
HX Mining
I Botany
J Agriculture
J1 Horticulture
J2 Feed
J3 Food
J4 Stimulant
J5 Oil
J6 Drug
J7 Fabric
J8 Dye
K Zoology
KZ Animal Husbandry
L Medicine
LZ3 Pharmacology
LZ5 Pharmacopoeia
M Useful arts
M7 Textiles [material]:[work]
Δ Spiritual experience and mysticism [religion],[entity]:[problem]
N Fine arts
ND Sculpture
NN Engraving
NQ Painting
NR Music
O Literature
P Linguistics
Q Religion
R Philosophy
S Psychology
T Education
U Geography
V History
W Political science
X Economics
Y Sociology
YZ Social Work
Z Law


A common example of the colon classification is:

  • "Research in the cure of the tuberculosis of lungs by x-ray conducted in India in 1950s":
  • Main classification is Medicine
    • (Medicine)
  • Within Medicine, the Lungs are the main concern
    • (Medicine,Lungs)
  • The property of the Lungs is that they are afflicted with Tuberculosis
    • (Medicine,Lungs;Tuberculosis)
  • The Tuberculosis is being performed (:) on, that is the intent is to cure (Treatment)
    • (Medicine,Lungs;Tuberculosis:Treatment)
  • The matter that we are treating the Tuberculosis with are X-Rays
    • (Medicine,Lungs;Tuberculosis:Treatment;X-ray)
  • And this discussion of treatment is regarding the Research phase
    • (Medicine,Lungs;Tuberculosis:Treatment;X-ray:Research)
  • This Research is performed within a geographical space (.) namely India
    • (Medicine,Lungs;Tuberculosis:Treatment;X-ray:Research.India)
  • During the time (') of 1950
    • (Medicine,Lungs;Tuberculosis:Treatment;X-ray:Research.India'1950)
  • And translating into the codes listed for each subject and facet the classification becomes
    • L,45;421:6;253:f.44'N5

See also[edit]


  1. ^ Raghavan, K. S (December 2015). "The colon classification :a few considerations on its future". Annals of Library and Information Studies. 62: 231–238.
  2. ^ GOPINATH (M A). Colon classification: Its theory and practice. Library Herald . 26, 1 - 2; 1987; 1 - 3.

Further reading[edit]

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