STRUCTURE OF EUROVOC
Current standards
The Eurovoc thesaurus has been compiled in accordance with the standards of the International Standards Organisation:
- ISO 2788-1986: Guidelines for the establishment and development of monolingual thesauri;
- ISO 5964-1985: Guidelines for the establishment and development of multilingual thesauri.
In all the language versions, the descriptors and non-descriptors are generally in the singular, and the plural is used when the singular does not correspond to normal usage.
Abbreviations have been avoided as far as possible in order to make the thesaurus easier to understand and use. Only the acronyms of well-known international organisations have been taken as descriptors. Reciprocal relationships are always established between the acronym and the unabbreviated form.
The alphabetical sorting of terms is not organised in a uniform manner for all language versions. No standard classification norm has yet been introduced in the management of the Eurovoc thesaurus.
Monitoring vocabulary
The role of the thesaurus is to remove ambiguities, ensuring that each descriptor is contextualised in such a way that its meaning is univocal. Each descriptor is limited to one meaning in the field to which it belongs.
A thesaurus is composed of:
descriptors, or preferred terms, used for indexing and denoting in an unambiguous fashion the concepts of the field covered by the thesaurus (for example, ‘application of legislation’);
non-descriptors, or non-preferred terms. Synonyms or non-descriptors are never intended as indexing terms. They are used as access points in the thesaurus and guide users to the appropriate descriptor with an instruction (USE, UF);
Examples:
application of legislation
- UF implementation of the law
- UF application of the law
- UF derogation from the law
- UF enforcement of the law
- UF implementation of the law
- UF validity of a law
implementation of the law
- USE application of legislation
semantic relationships, i.e. relationships based on meaning, firstly between descriptors and non-descriptors and secondly between descriptors.
If the meaning is not clear enough, a scope note, introduced by the symbol ‘SN’, can accompany a descriptor to clarify its meaning or use.
Example:
- A note on definition, if this clarifies the meaning of the descriptor:
share farming
SN: Arrangement under which the landowner lets his land in return for part of the produce.
- A note on use, if it provides guidance on how to use the descriptor:
retail price
SN: Use in opposition to wholesale price, otherwise use consumer price.
When homographs — terms with the same spelling but a different meaning — are taken as descriptors or non-descriptors, their meaning is clarified by an explanation in brackets.
Example:
- Land (Germany)
- department (france)
- conciliation procedure (part of co-decision procedure)
Structure
FIELDS AND MICROTHESAURI
At generic level Eurovoc has a two-tier hierarchical classification:
fields, identified by two-digit numbers and titles in words:
Example:
microthesauri, identified by four-digit numbers — the first two digits being those for the field containing the microthesaurus — followed by titles in words:
Example:
The numbering of fields and microthesauri is identical in all language versions.
SEMANTIC RELATIONSHIPS
At the specific level of descriptors and non-descriptors, the structure of Eurovoc depends on semantic relationships:
- microthesaurus relationship (MT);
- equivalence relationship (UF, USE);
- hierarchical relationship (BT, NT);
- associative relationship (RT).
Microthesaurus relationship
All descriptors are accompanied by a reference to a microthesaurus, introduced by the abbreviation MT (microthesaurus) to show to which microthesaurus or microthesauri they belong.
Example of a descriptor belonging to a single microthesaurus:
nationality
MT 1231 international law
Equivalence relationship
The equivalence relationship between descriptors and non-descriptors is shown by the abbreviations:
When a number of terms represent the same concept, the equivalence relationship clarifies which indexing term should be used. In the example above, the terms ‘technology park’ (which belongs to microthesaurus ‘6806 industrial structures and policy’) is the descriptor which must be used for indexing concepts such as ‘science park’.
In Eurovoc, reciprocity between descriptors and non-descriptors applies to:
Example:
IEA (OECD)
USE International Energy Agency (7621)
near-synonyms or terms considered as different in ordinary use but treated as synonyms for indexing purposes.
Examples:
slaughter of livestock
- USE slaughter of animals (6036)
technological dependence
- USE technological independence (0806)
In the case of terms which are marginal in relation to the fields covered by the thesaurus, the user is referred back to the generic term. The name of a class and of its members are treated as equivalents. The generic term of the class is then considered to be the descriptor.
Example:
- apple
- fig
- pear
- pome fruit
- quince
USE pip fruit (6006)
Hierarchical relationship
This relationship is based on hierarchical levels of superiority or subordination between descriptors. The superior term constitutes a class, whereas the subordinate terms represent elements or parts of this class. It is indicated by the abbreviations:
‘BT’ (broader term or generic term) between a specific descriptor and a more generic descriptor, together with an indication of the number of hierarchical steps between the specific descriptor and each broader term.
Example:
standard
- 1 standardisation
- BT2 technical regulations
Descriptors with no broader terms are called ‘top terms’.
‘NT’ (narrower term or specific term) between a generic descriptor and a specific descriptor, together with a figure showing the number of hierarchical steps between the generic term and each narrower term.
Example:
standardisation
- NT1 approval
- NT2 Community certification
- NT1 EC conformity marking
- NT1 harmonisation of standards
- NT1 international standard
- NT2 European standard
- NT1 standard
- NT2 production standard
- NT2 quality standard
- NT2 safety standard
- NT2 technical standard
The hierarchical relationship allows those using a documentary system to adapt its level of specificity by browsing in the hierarchy. They can expand or detail their question by selecting descriptors with a broader meaning (for example, ‘standardisation’, or ‘technical regulations’) or a more precise meaning (‘production standard’, ‘quality standard’, ‘technical standard’).
The hierarchical relationship clarifies the meaning of the descriptor in its context; for example, the sense in which the descriptor ‘press’ is to be understood is clarified by its being subordinated to the descriptor ‘mass media’.
Example:
press
- BT1 mass media
- BT2 means of communication
In Eurovoc, the hierarchical relationship is established on the basis of logical situations.
Generic relationship
This identifies the link between a class (superior term, broader term or top term) and its constituents (subordinate terms or specific terms).
Example:
protected area
- NT1 national park
- NT2 national city park
- NT1 nature reserve
Partitive relationship
Concerns a limited number of situations in which the name of a part indicates the name of the whole, regardless of the context. The name of the whole represents the superior term and the name of the part the subordinate term(s). In the framework of Eurovoc, it applies mainly to the following classes of terms:
Geometric places
Example:
ocean
- NT1 Antarctic Ocean
- NT1 Arctic Ocean
- NT1 Atlantic Ocean
- NT2 Baltic Sea
- NT2 English Channel
- NT2 Irish Sea
- NT2 North Sea
- NT2 Norwegian Sea
- NT1 Indian Ocean
- NT1 Pacific Ocean
Disciplines or areas of knowledge
Example:
chemistry
- NT1 analytical chemistry
- NT1 biochemistry
- NT2 enzyme
- NT1 electrochemistry
- NT1 photochemistry
Hierarchised social structures
Example:
bureau of parliament
- NT1 Deputy Speaker of Parliament
- NT1 Speaker of Parliament
- NT1 treasurer
(c) Polyhierarchical relationship
Some descriptors can belong to several fields at once for logical reasons. One of Eurovoc’s distinctive features is the limitation of polyhierarchy. Descriptors which could fit into a number of subject fields are thus generally assigned only to the field which seems the most logical for users.
However, polyhierarchy is accepted in the thesaurus for the fields ‘72 GEOGRAPHY’ and ‘76 INTERNATIONAL ORGANISATIONS’.
Descriptors which belong to these two fields can be subordinate to a number of broader terms.
For example, ‘Nigeria’ belongs to all of the following categories: ‘West Africa’, ‘ACP countries’, ‘OPEC countries’ and ‘CEAO countries’.
Thus the various policies of the European Union, which could logically belong to the field ‘EUROPEAN UNION’, are actually in the fields to which they directly relate.
For example, the descriptor ‘Common Agricultural Policy’ belongs to the field ‘56 AGRICULTURE, FORESTRY AND FISHERIES’, and the descriptor ‘Community research policy’ to the field ‘64 PRODUCTION, TECHNOLOGY AND RESEARCH’.
Example of a descriptor belonging to more than one microthesaurus:
Panama
- MT 7216 America
- MT 7231 economic geography
- MT 7236 political geography
Associative relationship
The associative relationship is a relationship between two descriptors which do not belong to the same hierarchical structure, although they have semantic or contextual similarities. The relationship between these two descriptors must be made explicit because it suggests to the indexer the use of other descriptors with connected or similar meanings which could be used for indexing or searches.
The associative relationship between descriptors is shown by the abbreviation RT (related term), placed between two associated descriptors.
Example:
standardisation
- RT European standardisation body
- RT industrial cooperation
- RT labelling
- RT mutual recognition principle
- RT quality label
- RT technical barrier
The associative relationship between two descriptors is reciprocal:
Examples:
credit guarantee
financial solvency
There is no associative relationship between descriptors with the same top term.
Examples:
There is no associative relationship between the descriptors ‘gaming’ and ‘sport’, which are subordinate to the same top term ‘leisure’ (microthesaurus ‘2826 social affairs’).
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