The Semantics of Business Vocabulary and Business Rules (SBVR) is a new OMG standard that is supposed to provide a conceptual framework for modeling a business domain in the form of a vocabulary and a set of rules.

In SBVR a business rule is defined in the following way:

business rule

rule that is under business jurisdiction

'Under business jurisdiction' is taken to mean that the business can enact, revise, and discontinue business rules as it sees fit. If a rule is not under business jurisdiction in that sense, then it is not a business rule, according to SBVR.

This SBVR definition seems too narrow for many purposes. E.g. SOX rules, or any other rules based on laws and external regulations, would not count as business rules according to this definition.

I think a wider definition (such as "rule that matters for the business") is more practical. So, we have to deal with two notions of "business rule": the narrow one defined by SBVR, and the wider one used in practice.