A component of a security clearance and/or security class used for computing access rights and controlling information flow by authorizing a specific group of subjects to have access to the information. Note: A When one or more caveats (of a given set) occurs within a security class, access rights are granted when: a) at least one of the caveats is present in the security clearance and b) the security clearance contains no caveat that is not also present in the security class (i.e., the caveats in the clearance are a non- empty subset of those in the security class. ) Adding a caveat to a group of caveats (of the same set) in a security class extends the group of subjects who may have access. See also: Category, Classification, Dominance.