[Contents]
Abbreviations and Acronyms have been included in the thesaurus where they have been adopted as standard railway terminology. In most cases the short form is a non-preferred term (for example FORI USE fibre optic route indicator) unless the full term has become archaic or is seldom used (e.g. Advanced Passenger Train USE APT ).
The name given to the display of all the terms in a thesaurus (preferred, non-preferred and guide terms) when displayed in alphabetical sequence in a book or computer display.
The relationship between terms which have much in common but do not have a parent/child or sibling relationship (i.e. Related terms).
A Broader Term is broader in scope than the terms below it in the Hierarchy. A Broader Term may have many narrower terms. A Narrower Term may itself be a Broader Term to even more specific terms below it in the hierarchy. For example locomotive is the broader term of tank locomotive, which is the broader term of saddle tank locomotive.
A Candidate Term is a new term, which has been proposed by users for inclusion in the thesaurus. Each term will be reviewed by the Railway Terminology Working Group and a decision will be made as to whether the term should be included as a Preferred or Non-Preferred Term and placed into the thesaurus accordingly.
The highest term within a Hierarchy. These terms are used merely as grouping terms to aid retrieval and as such are Non-Index Terms.
A Company Term is a term used by a particular railway company or small group of companies that is not in general usage (e.g. signal cabin USE signal box; lead USE turnout).
Complex Compound Terms are divided up into single concepts (for example, first class return privilege ticket USE first class ticket and return ticket and privilege ticket), except where this affects the meaning (for example, combination brake and ejector valve), or where the use of such a term is well established.
The relationship between Preferred terms and Non-preferred terms.
A Non-Index Term, indicating the concept by which Narrower Terms are grouped within that facet. In this thesaurus the facet indicator appears in angle brackets and is printed in normal type (fo r example, <locomotives by power source>).
Foreign terms which are well established within the English language, are included within the thesaurus. They normally have Non-preferred term status (for example, wagon lit USE sleeping car), unless there is no exact English equivalent (for example, capuchon or car gwyllt).
The Hierarchical relationship between Broader Terms and Narrower Terms. This relationship follows the 'all-and-some' rule (for example, all steam locomotives are locomotives but only some locomotives are steam locomotives, consequently locomotives is a Broader term of steam locomotives).
A Non-index term used to bring together other terms with a common concept. In this thesaurus grouping terms appear in angle brackets and are printed in normal type, (for example <point and signal actuation>.
The name given to the layout of the Hierarchy of Preferred Terms, Grouping Terms and Facet Indicators when displayed in a book or computer display.
The relationship between Broader Terms and Narrower Terms. In this thesaurus all of the relationships are of the generic type (see Generic relationship above).
An arrangement of terms showing broader-narrower relationships between them.
Homographs (or Homonyms) are terms that have the same spelling but different meanings. In this thesaurus these are distinguished by a qualifier in round brackets (for example, dart (smokebox) and dart (fire iron)). The use of Homographs has been restricted within the thesaurus. Where they do appear, they may have an effect on computerised retrieval. This problem and a possible solution should be noted in recording guidelines for the specific system being used to ensure adequate retrieval (for example, always query using a wild card symbol following the term).
Hyphens are not used in the thesaurus as their inclusion inhibits retrieval. Therefore hyphenated words are treated as two words.
A term that can be used to describe a railway object in records on a database (for example, carriage). In this thesaurus, Index Terms appear in lower case, bold type (with capitalised initial letters only if proper names).
Natural Language Order is used for all Preferred Terms (for example, electric locomotive, not locomotive, electric).
An authoritative, dated, published source which makes specific reference to the term, giving it validation.
To retrieve and record different facets of particular objects, it is possible to index with more than one Preferred Term (for example, the bogie to a railway carriage could be indexed using: bogie and carriage component).
A term that represents a more specific concept than its 'parent' in the hierarchy (for example, saddle tank locomotive is a Narrower Term of tank locomotive). A Narrower Term can have more than one Broader Term (BT). For example, Pullman car is a Narrower Term of both <passenger carriages by class> and <rolling stock by ownership>. However, due to software limitations, such Polyhierarchical Relationships are kept to a minimum in the current version.
A Non-Index Term (or Guide Term) is a term that cannot be used as an Index Term, but is useful in the thesaurus as a grouping term for retrieval purposes only. Non-index terms include Grouping Terms (for example, <point and signal actuation>) and Facet Indicators (for example, <locomotives by power source>). Non-Index Terms are distinguished in this thesaurus by appearing in lower case and normal weight typeface, in angle brackets.
A Non-Preferred Term is a term that should not normally be used for indexing (for example, because it is synonymous with a term that is already in the thesaurus), but which is retained in the thesaurus to point the user to a Preferred Term which should be used instead (for example, dummy USE ground signal). If searches are undertaken using software that supports thesauri, the cross-referencing will be performed automatically. When a non-preferred term is entered as part of a search query, the software will retrieve records indexed with the equivalent preferred term.
Museums specific to a particular railway company may occasionally choose to adopt a different term as the preferred term for internal usage if that company used different terminology from the rest of the industry. A means of mapping between systems would be needed if they then wished to share information via any future cross-database searching facility.
A Polyhierarchy allows a Preferred Term to belong to more than one Class or to have more than one Broader Term. This thesaurus is polyhierarchical although multiple Broader Term relationships have been kept to a minimum until the software implications have been fully evaluated.
A term that can be used for indexing. Preferred Terms appear in lower case bold typeface within this thesaurus.
Punctuation has generally been omitted from the hierarchical and alphabetical lists within the thesaurus as its inclusion inhibits retrieval. However, it has always been retained within the scope notes to ensure that the definition is understandable. Punctuation has also been retained within preferred terms where its omission could cause ambiguity (e.g. locomotive-tender coupling - specifically the coupling that joins locomotive and tender, not the conventional coupling at the other end of a locomotive tender as might be implied if the hyphen was omitted).
Standard English is used wherever possible for Preferred Terms. However, where a Regional or Dialect Term has no recognised equivalent, that term will be accepted as the Preferred Term.
A related term is a Preferred Term which can be linked to another Preferred Term conceptually but not hierarchically (for example, rack rail and rack railway). The thesaurus allows for terms to be related in the same hierarchy when a particularly strong link occurs.
A definition of a term and/or guidance on its use. The definition is limited to this thesaurus and may be more precise than in normal usage.
Railway objects appear in the Singular apart from instances where the Plural is the common usage (for example, sheerlegs) or where the Singular changes the meaning (for example, points not point).
A term having a different form/spelling but the same or nearly the same meaning as another term (for example, coach and carriage). The thesaurus controls the use of Synonyms and quasi-synonyms to improve indexing and retrieval, by the use of Preferred and Non-Preferred Terms. Where Non-Preferred Terms have several meanings, there can be more than one Preferred Term and guidance on their use may be given by a Scope Note.
The treatment of Narrower Terms as if they are equivalent to, rather than a species of their Broader Terms. Upward posting is used where the level of detail suggested by a term is considered too specific for the thesaurus.
Use indicates the Preferred Term which should be used for a Non-Preferred Term (for example, coach USE carriage).
Use For usually abbreviated to UF, indicates the Non-Preferred Term(s) covered by a Preferred Term. For example:
|
carriage | ||
|
UF |
car | |
|
coach | ||
A dated, authoritative source which gives a term validation. Warrant may be provided by a published source (see Literary Warrant) but acknowledged experts in the field may also provide verification.
The alphabetisation of the terms within the alphabetical list of the thesaurus follows the word-by-word format whereby terms are listed alphabetically by word as opposed to letter-by-letter.
If we look at the following list of words we find they can be listed differently according to the format of the alphabetisation:
|
Word-by-word |
Letter-by-letter | |
|
fire bar |
fire bar | |
|
fire bucket |
firebox | |
|
fire hole |
firebox door | |
|
fire iron |
fire bucket | |
|
firebox |
fire hole | |
|
firebox door |
fire iron |
The leading angle bracket on grouping terms and facet indicators is ignored in the alphabetical arrangement.
|
fixed headcode lamp |
| |
|
<fixed lighting components> |
| |
|
<fixed lighting> |
| |
|
fixed propulsion stock |
| |
|
fixed signal |
| |
|
<fixed signal boards> |
| |
|
fixed signal (inoperable) |
| |
|
fixed tail lamp |
|
| © Collections Trust 2002. You may freely download this page for non-profit use, but must acknowledge Collections Trust (formerly MDA) & the Railway Terminology Working Group in any output in which it is used. |