Software in a specific domain has several characteristics and each characteristic should be fixed when the software requirements are specified. In addition, these characteristics sometimes correlate with each other. However, we sometimes forget to specify several characteristics and/or to take their correlations into account during requirements elicitation. In this paper, we propose a meta-model for representing such characteristics and their correlations, and also propose a method to build a model for a specific domain by using documents about existing software systems. By using our model for a domain, a requirements specifi- cation for a system in the domain could be complete and unambiguous because requirements analysts can check the characteristics that should be decided. The specification could be also correct and consistent because the analysts can know side effects of a requirement change by using correlation among the characteristics. We have applied our methods to a case study for confirming the usefulness of such model and the methods.