About the Thesaurus

The Transport Canada Thesaurus (TCT)  has been developed as a specialized controlled vocabulary to be used as a source of standardized terminology for the indexing and retrieval of Transport Canada information resources. Its main function is to standardize the form, meaning and use of index terms so as to ensure that subjects and concepts will always be represented in the same way.

Background

The TCT content is founded upon the US-based Transportation Research Board’s Transportation Research Thesaurus (TRT) http://www4.trb.org/trb/tris.nsf/web/trt

Scope and exclusions

The TCT has been developed on the basis of extracting broad, high-level terminology used in documents found on the Transport Canada web sites (intranet and internet) and publications housed in the Transport Canada Library collection. It does not include geographical names, titles (e.g., of surveys), proper names (e.g., of companies) and acronyms, except where they are in common usage

Thesaurus Structure

The TCT is a post coordinated thesaurus where most concepts are represented by single words. Compound terms are used when there is no alternative or when that phrase is commonly used to represent that concept, for example Accident investigation sites

Terms are in direct (not inverted) format, as they would be in natural speech; for example, "Admiralty law" not "Law, Admiralty” Terms may be accompanied by scope notes which provide a brief explanation of intended coverage or proper usage of a term.

In English and in French, countable nouns are presented in the plural form (e.g. Airports, Aéroports), while collective or abstract nouns are displayed in the singular form (e.g. Energy)

Spelling
The Transport Canada Library uses the American spelling of terms, with cross references (USE)  from variant spellings. Example:

        Behaviour
            USE: Behavior.
 

Languages

The Transport Canada Thesaurus is a bilingual (English-French) resource. Neither language is to be considered the dominant or source language.

Ownership
The Transport Canada Library owns and is responsible for the maintenance of the Transport Canada Thesaurus.

Audience

The intended audience for this resource consists of librarians, content providers, indexers, Web developers and communications personnel.

Thesaurus Structure and Display

The relationships contained in the Thesaurus are hierarchical (broader / narrower), associative (related) or prescriptive (use / used for).  For more information about these types of relationships, see below.

        Definitions  ¹  

Broader term:  A descriptor to which another descriptor or multiple descriptors are subordinate in a hierarchy.

Descriptor: A type of heading that is a term chosen as the preferred expression of a concept in the thesaurus.

Entry term: The nonpreferred term in a cross reference that leads to a descriptor in a thesaurus. Also know as "lead-in term". The relationship indicator for this type of term is USE; its reciprocal is UF (used for)

Hierarchy: Generic (broader) specific (narrower) or whole-part relationships, which are generally indicated in a thesaurus through code or indentation. See also broader term; narrower term.

Narrower term:  A descriptor that is subordinate to another descriptor or to multiple descriptors in a hierarchy.

Postcoordination: The combining of descriptors at the searching stage rather than at the subject heading list construction stage or indexing stage.

Preferred term: One of two or more synonyms or lexical variants that servers as a descriptor

Nonpreferred term: One of two or more synonyms or lexical variants that serves as an entry term

Related term: A descriptor that is associatively but not hierarchically linked to another descriptor in a thesaurus.

Scope note: A note following a descriptor explaining its coverage, specialized usage, or rules for assigning it.

Use:  An equivalence relationship which leads from a non-preferred term to a descriptor and accommodates synonyms, quasi-synonyms, and lexical variants.

Used for: The reciprocal of a "Use" relationship which records non-preferred terms.
 

  ¹ ANSI/NISO Z39.19-2003 Guidelines for the Construction, Format, and Management of Monolingual Thesauri. National Information Standards Organization. 28-Aug-2003  (Glossary of terms: pp 35-38).  Available from NISO
 

Sample Entries

    Preferred Subject Term

Airports            

     French: Aéroports
     Scope Note

A certified, large area of level land where aircraft land and take off, that usually has paved runways, a control tower, hangars, maintenance facilities, refueling facilities, and often includes a building for passengers and cargo.

    Used For

Aeronautical facilities
Aviation facilities

    Broader Term

Aerodromes

    Narrower Term

Heliports
International airports
Private airports

    Related Term:

Air traffic control facilities
Airport facilities
Airstrips
Runways

    Non preferred  term (also called Entry or Lead in term):

Aeronautical facilities  

        French: Équipements aéronautiques

        USE: Airports

Other Canadian Government Thesauri

Statistics Canada Thesaurus: http://www4.statcan.ca/english/thesaurus/index.htm
Government of Canada Core Subject Thesaurus: http://en.thesaurus.gc.ca/intro_e.html

Related Sites

Thesauri and controlled vocabularies -National Library of Canada http://www.collectionscanada.ca/8/4/r4-280-e.html
US Transportation Research Board Online Thesaurus: http://trt.trb.org