This paper introduces selected latest results of a research in situation based product definition. The current representative method of product definition applies situation based control of product feature parameters. In the presented method, application of situation control was improved by placing it from the product feature level to the product behavior level. Because the feature level situation control is a proven key technology in product lifecycle management systems, the new behavior level product definition process controls the process of the feature level product definition. This paper starts with a comparison of the feature and the behavior level product feature definition. Following this, the product request, product behavior, and context structure feature definitions are introduced as main elements of the behavior level product feature definition process. Next, a new context structure and its connection with the feature sequence is exampled and discussed. Finally, application of the proposed method in product lifecycle management systems is outlined.