This paper proposes a new objective metric called the SEMCON to enrich existing concepts in domain ontologies for describing and organizing multimedia documents. The SEMCON model exploits the document contextually and semantically. The preprocessing module collects a document and partitions that into several passages. Then a morpho-syntatic analysis is performed on the partitioned passages and a list of nouns as part-of-speech (POS) is extracted. An observation matrix based on statistical features is then computed followed by computing the contextual score. The semantics is then incorporated by computing a semantic similarity score between two terms - term (noun) that is extracted from a document and term that already exists in the ontology as a concept Eventually, an overall objective score is computed by adding contextual score with semantic score. Subjective experiments are conducted to evaluate the performance of the SEMCON model. The model is compared with state-of-the-art tf*idf and χ 2 (Chi square) using FI measure. The experimental results show that SEMCON achieved an improved accuracy of 10.64 % over the tf*idf and 13.04 % over the χ 2 .