The Collaborative International Dictionary of English v.0.48:

Broadcast \Broad"cast`\, n.
   1. (Agric.) A casting or throwing seed in all directions, as
      from the hand in sowing.
      [1913 Webster]

   2. an act of broadcasting; specifically, a program in which
      sounds or images are transmitted in all directions from a
      radio or television station; -- usually referring to a
      scheduled program on a commercial or public service radio
      or television station, using the normal radio frequencies
      for those media, in contrast to a radiotelephone
      conversation, which may also be transmitted in all
      directions, but is intended for receipt by a base station
      in the telephone network.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Broadcast \Broad"cast`\, a.
   1. Cast or dispersed in all directions, as seed from the hand
      in sowing; widely diffused.
      [1913 Webster]

   2. Scattering in all directions (as a method of sowing); --
      opposed to planting in hills, or rows.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Broadcast \Broad"cast`\, adv.
   So as to scatter or be scattered in all directions; so as to
   spread widely, as seed from the hand in sowing, or news from
   the press.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Broadcast \Broad"cast`\, v.
   1. to cast or disperse in all directions, as seed from the
      hand in sowing; to diffuse widely.
      [1913 Webster]

   2. to transmit (sounds, images, or other signals) in all
      directions from a radio or television station.
      [PJC]

   3. to disseminate (information, a speech, an advertisement,
      etc.) from a radio or television station.
      [PJC]

   4. to spread (information, news, gossip) widely by any means.
      [PJC]

WordNet (r) 3.0 (2006):

broadcast
    n 1: message that is transmitted by radio or television
    2: a radio or television show; "did you see his program last
       night?" [syn: broadcast, program, programme]
    v 1: broadcast over the airwaves, as in radio or television; "We
         cannot air this X-rated song" [syn: air, send,
         broadcast, beam, transmit]
    2: sow over a wide area, especially by hand; "broadcast seeds"
    3: cause to become widely known; "spread information";
       "circulate a rumor"; "broadcast the news" [syn: circulate,
       circularize, circularise, distribute, disseminate,
       propagate, broadcast, spread, diffuse, disperse,
       pass around]

Moby Thesaurus II by Grady Ward, 1.0:

198 Moby Thesaurus words for "broadcast":
   accessible, advertise, advertisement, affirmed, air, airing,
   announce, announced, announcement, annunciate, attenuation,
   bandying, beam, bed, bestrew, blazon, book, broadcasting,
   brought to notice, bruit about, bruiting, bruiting about,
   canned show, circulated, circulation, circumfuse, circumfusion,
   commercial, commercial program, common knowledge, common property,
   communicate, convey, current, deal out, declared, dibble, diffract,
   diffraction, diffuse, diffused, diffusion, dilution, discrete,
   dispensation, dispense, dispersal, disperse, dispersed, dispersion,
   display, dispread, disseminate, disseminated, dissemination,
   dissipated, dissipation, distribute, distributed, distribution,
   diverge, divergence, drill, electrical transcription, evaporation,
   evulgation, expansion, fan out, forest, fragmentation, get across,
   get over, give, give word, hand on, impart, implant,
   in circulation, in print, inseminate, insemination, issuance,
   issue, leave word, made public, make known, network show, newscast,
   open, overscatter, oversow, overspread, pass, pass along, pass on,
   peppering, periodical, plant, planting, pot, printing, proclaim,
   proclaimed, proclamation, promulgate, promulgation, pronouncement,
   pronunciamento, propagate, propagated, propagation, public,
   publication, publish, published, publishing, put in, radiate,
   radiation, radio, radio fare, radiobroadcast, rebroadcast,
   reforest, reforestation, relay, render, report, reported, rerun,
   reset, resetting, retail, retimber, retimbering, scatter,
   scatter seed, scattered, scattering, scatterment, seed, seed down,
   seeding, seminate, semination, send, send word, serial, set,
   setting, share, share with, shortwave, shotgun pattern, show,
   sign off, sign on, signal, soap opera, sound effects, sow,
   sow broadcast, sowing, sparse, spattering, splay, sporadic,
   sportscast, spread, spread out, spreading, spreading abroad,
   sprinkling, stated, straggling, straggly, straw, strew, strewing,
   strewn, strown, sustainer, taped program, telecast, telecasting,
   televise, televised, tell, transfer, transmission, transmit,
   transplant, transplantation, utter, ventilation, volatilization,
   widespread, wireless



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

broadcast

   A transmission to multiple, unspecified recipients.  On
   Ethernet, a broadcast packet is a special type of multicast
   packet which all nodes on the network are always willing to
   receive.