In this paper, we present two facets indispensable for the efficiency of our information retrieval system: meta-documents and query extension. Meta-document represents a structure used to annotate our web documents collection and query extension represents an automatic process aimed to enhance user query expression by additional terms. The two facets are indirectly related since added terms to a given query are taken from an ontology based on meta-documents. The cooperation between meta- documents and query extension aims to have an enhanced information retrieval process. In this paper, we present our proposition particularity and its evaluation results which show its efficiency.