37 CFR § 42.401 - Definitions.
In addition to the definitions in § 42.2, the following definitions apply to proceedings under this subpart:
Applicant includes a reissue applicant.
First publication means either a patent or an application publication under 35 U.S.C. 122(b), including a publication of an international application designating the United States as provided by 35 U.S.C. 374.
Petitioner means a patent applicant who petitions for a determination that another party named in an earlier-filed patent application allegedly derived a claimed invention from an inventor named in the petitioner's application and filed the earlier application without authorization.
Same or substantially the same means patentably indistinct.