This work focuses on the design and the development of a context ontology model, based on a domain ontology enriched, by lexico-semantic relations defining the lexical functions introduced by Mel'cuk in the Meaning-Text Theory, and by the concept of the context, in order to improve the analysis and the detection of meaning in text. This is motivated, by the fact that, unstructured data constitute the majority of produced contents, requiring for their exploitation, the development of tools and technologies allowing their integration into knowledge-based and reasoning-based systems. Existing technologies in the analysis and the extraction of semantic information from text can have a lot of imperfections; indeed, important elements such as concept of the context and use of all possible relations between terms, are not fully and formally supported. It is why we propose an extended model of a domain ontology as a context (in our case an ontology of fauna and flora), enriched by aspects that can help to address the cited problems. Such ontologies constitute the basis of an advanced approach for the detection and the extraction of contextual and semantic information from text, published in a parallel article (H.Fadili ACS/IEEE, 2013).