of them being rock names. The dictionary structure and conversion procedures required to get the ontology are described in [13] and most important below.

Vocabulary: Words are connected by letter " **" in compound terms.**
Article title**: The dictionary article title contains a Russian term and its English**
equivalent in a simple case, but its both Russian and English synonyms are often specified as well. Each term present in the title generates an ontology class. Thus, the ontology will contain classes in Russian and in English. All terms from one title are considered synonyms, i.e. their classes are declared equivalent. These conversions resulted in 3,179 classes and 1,659 class equivalence axioms having appeared in the ontology.

The text of the article**: The basic dictionary article text parts are: term definition,**
comment, list of links to references (normally at the end), term origin description
(normally located on the list of references after the article, in which **the term was**
introduced). Comments and a list of links to references located in some parts of the ontology in the form of separate annotations are supposed **to be selected** from the text of the article.

The dictionary ontology (DL species is ALUF(D)) is published3 **and can be**
viewed using any ontology browser at this moment.

Collective management of scientific term definitions. **Another copy of**
the ontology is accessible by means of webProtege 4**installed on the Geology**
portal5**. The dictionary ontology is 'dic' there.**
It is important that a prefix and a namespace be assigned to each dictionary.

We have for terms of the ontology itself, terms from the Moscow State University Geoweb portal, terms from the Petrographic Code of Russia [8], and **terms from** the [7] dictionary, respectively: prefix dic: <//earth.jscc.ru/ontologies/dic.owl\#> prefix gwr: <//wiki.web.ru/wiki\#> prefix pgcc: <//www.igem.ru/site/petrokomitet/code\#> prefix pgc: <//www.igem.ru/site/petrokomitet/slovar\#>
A formal term meaning definition is critical for developing a formal theory.

For example, the current version of the dictionary provides a formal definition of the abessedite rock type (see Portlet Axioms for dic:abessedite), and namely peridotite and minerals **mixture and** contains **mineral only (olivin or hornblende or phlogopite)**
This formula is written using the Manchester OWL syntax. It is important that petrologists are able to read it. The process of obtaining a formal (mathematical) definition, especially in a form clear to experts, is described **further,**
3 http://earth.jscc.ru/ontologies/dic.owl 4 http://protegewiki.stanford.edu/index.php/WebProtege 5 http://earth.jscc.ru/webprotege/