Standard terminology for the book indexer system. Terms align with ISO 999:1996, Chicago Manual of Style, and ASI best practices.
Entry The complete unit in an index. Contains a heading, zero or more subentries, zero or more locators, and zero or more cross-references. An entry must have at least one locator OR one cross-reference.
Heading The text term that names an entry. A noun or noun phrase. The heading is what readers look up alphabetically. Also called "headword" in some sources.
Subentry A child entry nested under a parent entry. Has its own heading, locators, and optional cross-references. Represents a more specific aspect of the parent concept. Subentries can have their own subentries (sub-subentries), but convention limits depth to 3 levels.
Locator A reference to where content appears in the source text. The term is intentionally broader than "page number" to accommodate different reference types.
| Locator Type | Example | Description |
|---|---|---|
| page | 45 | Single page reference |
| page_range | 45-48 | Contiguous pages discussing the topic |
| footnote | 45n, 45n3 | Footnote on a page (optionally numbered) |
| figure | fig. 12 | Reference to a figure |
| table | table 3.1 | Reference to a table |
| chapter | ch. 3 | Chapter-level reference |
Cross-reference A link between entries. Points readers from one term to another. Two primary types exist.
See reference Directs the reader from a non-preferred term to the canonical term. The entry with a See reference has no locators of its own — all information is under the target entry.
Labor unions. See Unions, labor
See also reference Points to related entries with additional information. Appears after locators. The current entry has its own content; the target has supplementary content.
Labor unions, 45-47, 112. See also Worker rights
See under / See also under Variants that clarify hierarchical position. Used when the target is a subentry rather than a main entry.
Organized labor. See under Unions
Double posting Creating multiple access points for the same concept under different headings. Both entries have identical locators. Increases discoverability.
Design, furniture, 223
Furniture design, 223
Flipped entry A form of double posting where word order is inverted.
African Americans, business ownership, 247-248
Business ownership, African Americans, 247-248
Index entries form a tree structure:
Entry (main heading)
├── Locator(s)
├── Cross-reference(s)
└── Subentry (subheading)
├── Locator(s)
├── Cross-reference(s)
└── Sub-subentry (rare)
└── Locator(s)
Maximum conventional depth: 3 levels (entry → subentry → sub-subentry).
These terms describe output format, not data structure. Included for completeness.
Indented style Subentries appear on separate lines with visual indentation.
Democracy, 12
Athenian origins, 45-47
modern challenges, 203-210
Run-in style Subentries follow the main heading on the same line, separated by punctuation.
Democracy, 12; Athenian origins, 45-47; modern challenges, 203-210
Core entities for the system:
| Entity | Contains | Relationships |
|---|---|---|
| Entry | heading, justification | has many Subentries, Locators, CrossReferences |
| Subentry | heading, justification | belongs to Entry, has many Locators, CrossReferences |
| Locator | type, value, justification | belongs to Entry or Subentry |
| CrossReference | type (see/see_also), justification | belongs to Entry or Subentry, references target Entry |
Justification fields support the success criteria requirement for human-readable explanations of each decision.