A domain model, or Domain Object Model (DOM) in problem solving and software engineering can be thought of as a conceptual model of a system which describes the various entities involved in that system and their relationships .
DOMAIN MODEL INCLUDE THE FOLLOWING
User interface requirements: automatic entry of products and easy to use data entry screens for web customer.
Processing requirements: Fast, automatic calculation of sales totals and shipping cost.
Storage requirements: fast retrieval and up-to-date of data from product, pricing, and customer databases. •Control requirements: signals for data entry errors and quick email conformation for customers.
Well, A domain is the subject matter (i.e. the world that you're modelling), and a model tries to explain a concept/subject concisely.
Thus a domain model (=conceptual model) tries to explain the domain concisely.
Thus a business model would explain what a business does, and therefore a business would be the same as a domain, except that a domain is broader, it's not just limited to a business.