According to S. R. Ranganathan, "Spot Subject" is a

The correct answer is the Subject of small extension and great intention.

Key Points

• According to Ranganathan, A spot subject, in his definition, was a subject with a very tiny extension (scope) and significant intension (meaning) and could often be encapsulated in a single sentence or word.
• This concept of a spot subject is somewhat similar to the idea of subject-specific keywords.
• Ranganathan also discussed the idea of a "concept space" where subjects are represented as points, similar to points on a line or plane.
• He asserted that while the concept of space is finite, the number of specific subjects within it could be infinite.

Additional Information

• Ranganathan categorized all the subjects in the universe of knowledge into three categories:
  • ​Basic Subjects (BS),
    • ​Primary (BS): Primary basic subjects are the main classes or categories that form the foundation of a classification system.
      • These are the fundamental subjects that encompass broad areas of knowledge.
    • Non-primary (BS): Non-primary basic subjects are subcategories or subdivisions of the primary basic subjects.
      • They represent narrower and more specific areas of knowledge within the broader primary subjects. 
  • Compound Subjects:
    • ​Compound subjects are subjects that are virtually infinite in number and are formed by combining a primary basic subject with a specific focus or qualifier.
    • These qualifiers help narrow down and specify the subject further.
  • Complex Subjects:
    • ​Complex subjects are composed of two phases or aspects.
    • They typically involve a primary basic subject combined with another aspect or specialization.