WordNet (r) 3.0 (2006):

broadband
    adj 1: of or relating to or being a communications network in
           which the bandwidth can be divided and shared by multiple
           simultaneous signals (as for voice or data or video)
    2: responding to or operating at a wide band of frequencies; "a
       broadband antenna" [syn: broadband, wideband]

The Free On-line Dictionary of Computing (30 December 2018):

broadband

    A class of communication channel capable of
   supporting a wide range of frequencies, typically from audio
   up to video frequencies.  A broadband channel can carry
   multiple signals by dividing the total capacity into multiple,
   independent bandwidth channels, where each channel operates
   only on a specific range of frequencies.

   The term has come to be used for any kind of Internet
   connection with a download speed of more than 56 kbps,
   usually some kind of Digital Subscriber Line, e.g. ADSL.
   A broadband connection is typically always connected, in
   contrast to a dial-up connection, and a fixed monthly rate
   is charged, often with a cap on the total amount of data that
   can be transferred.  Domestic broadband connections typically
   share a telephone line with normal voice calls and the two
   uses can occur simultaneously without interference.

   See also baseband, narrowband.

   (2006-03-30)