48 CFR 1.501-1: 1.501-1 Definition.

Significant revisions, as used in this subpart, means revisions that alter the substantive meaning of any coverage in the FAR System and which have a significant cost or administrative impact on contractors or offerors, or a significant effect beyond the internal operating procedures of the issuing agency. This expression, for example, does not include editorial, stylistic, or other revisions that have no impact on the basic meaning of the coverage being revised.