In recent years many efforts were dedicated to the elicitation and definition of requirements for software development projects. However, by concentrating requirement discussions on software development there is a tendency to neglect the predominant role of standard application software (SAS) in enterprises. The process of choosing a SAS product is poorly understood, frequently ill-structured, and performed in an inefficient and ineffective way leading to suboptimal results. Focusing functional aspects, this paper suggests an approach for describing business requirements and software characteristics in terms of ontologies. This way a formal representation of both, requirements and software features, becomes available and can be used for semi-automated reasoning about the suitability of a certain product. The paper contributes directly to the requirements engineering research and addresses a widely ignored topic by suggesting a solution proposal for the above sketched problem.