As used in this chapter—

(1) “clerk” means the clerk of the court in which the petition for the review of an order, reviewable under this chapter, is filed;

(2) “petitioner” means the party or parties by whom a petition to review an order, reviewable under this chapter, is filed; and

(3) “agency” means—

(A) the Commission, when the order sought to be reviewed was entered by the Federal Communications Commission, the Federal Maritime Commission, or the Atomic Energy Commission, as the case may be;

(B) the Secretary, when the order was entered by the Secretary of Agriculture or the Secretary of Transportation;

(C) the Administration, when the order was entered by the Maritime Administration;

(D) the Secretary, when the order is under section 812 of the Fair Housing Act; and

(E) the Board, when the order was entered by the Surface Transportation Board.