If speeds don't reach the threshold, Internet providers cannot call the connection "broadband." Under the new standard, about one-fifth of Americans would lack access to "high-speed" Internet.

The Federal Communications Commission on Thursday voted to change the definition of broadband to connection speeds of 25 megabits per second or higher, casting aside the previous standard of 4 megabits per second.

Many Internet service providers had opposed the definition change. The ruling enhances the FCC's legal power to push providers to boost connection speeds to levels it deems suitable.

Read MoreNet neutrality decision expected from FCC in February

The FCC could also use the scope of the law to allow easier entry into broadband markets, including by municipalities. The change comes amid a pending $45 billion merger of Comcast and Time Warner Cable, giants who the rule would affect.

Comcast holdings include NBCUniversal, the parent company of CNBC.



The FCC could also use the standard to guide its decisions on doling out subsidies that encourage broadband deployment and network improvements. The agency has not typically used reports like the one that set the broadband definition to tighten regulations, experts told Reuters.

This year has already proven busy for the government agency, which on Tuesday warned hotels and other entities not to block access to personal Wi-Fi hotspots. It also continues to consider proposals on net neutrality law.

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—Reuters contributed to this report.