62 switched network to encompass users with IP addresses in addition to users with telephone numbers, mobile broadband still fails to qualify as an “interconnected service.” We reject both arguments. In mobile petitioners’ view, mobile broadband (or any non-telephone mobile service)—no matter how universal, widespread, and essential a medium of communication for the public it may become—must always be considered a “private mobile service” and can never be considered a “commercial mobile service.” Nothing in the statute compels attributing to Congress such a wooden, counterintuitive understanding of those categories. Rather, Congress expressly delegated to the Commission the authority to define—and hence necessarily to update and revise—those categories’ key definitional components, “public switched network” and “interconnected service.” 47 U.S.C. § 332(d); see 2015 Open Internet Order, 30 FCC Rcd. at 5783–84 ¶ 396. “In this sort of case, there is no need to rely on the presumptive delegation to agencies of authority to define ambiguous or imprecise terms we apply under the Chevron doctrine, for the delegation of interpretative authority is express.” Women Involved in Farm Economics v. U.S. Department of Agriculture, 876 F.2d 994, 1000–01 (D.C. Cir. 1989) (citation omitted); see Rush University Medical Center v. Burwell, 763 F.3d 754, 760 (7th Cir. 2014); 2015 Open Internet Order, 30 FCC Rcd. at 5783 ¶ 396 & n.1145. We find the Commission’s exercise of that express definitional authority to be a reasoned and reasonable interpretation of the statute. We therefore sustain the Commission’s reclassification of mobile broadband as a commercial mobile service against mobile petitioners’ challenges. In light of that disposition, we need not address the Commission’s alternative finding that mobile broadband, even if not a commercial