17 U.S.C. § 1501

1. (1)the term “claimant” means the real party in interest that commences a proceeding before the Copyright Claims Board under section 1506(e), pursuant to a permissible claim of infringement brought under section 1504(c)(1), noninfringement brought under section 1504(c)(2), or misrepresentation brought under section 1504(c)(3);
2. (2)the term “counterclaimant” means a respondent in a proceeding before the Copyright Claims Board that—
   1. (A)asserts a permissible counterclaim under section 1504(c)(4) against the claimant in the proceeding; and
   2. (B)is the real party in interest with respect to the counterclaim described in subparagraph (A);
3. (3)the term “party”—
   1. (A)means a party; and
   2. (B)includes the attorney of a party, as applicable; and
4. (4)the term “respondent” means any person against whom a proceeding is brought before the Copyright Claims Board under section 1506(e), pursuant to a permissible claim of infringement brought under section 1504(c)(1), noninfringement brought under section 1504(c)(2), or misrepresentation brought under section 1504(c)(3).