Uniterms

Uniterms refers to single-word descriptors used in certain manual and early mechanized indexing systems and, by extension, to the indexing method built around them. The most widely known application, often called the Uniterm system, emerged in the mid‑20th century as an approach to coordinate indexing: documents were described by a set of uniterms (keywords), and retrieval was achieved by intersecting lists or card files for two or more terms to locate items matching a combination of concepts.

Historically associated with information scientists and practitioners seeking more flexible alternatives to strict classification schemes, the Uniterm approach emphasized rapid indexing, ad hoc vocabulary, and user-centered access. Files of cards or punched catalogs allowed indexers to add new uniterms without reorganizing a hierarchical classification, and users could perform compound searches by combining term headings.

Advantages of uniterm-based indexing included adaptability, simplicity of concept assignment, and support for multi-faceted queries. Limitations included inconsistent term assignment, synonymy and ambiguity, large manual maintenance requirements, and difficulties scaling without automation. With the advent of computerized retrieval, controlled vocabularies, and full-text searching, pure uniterm card systems largely fell out of use, though the underlying idea of keyword indexing persists in modern search engines, tagging systems, and many subject access methods. The term "uniterms" is also used generically to mean individual keywords or index terms in diverse indexing contexts.