Viacom's rhymes with:
telecom's, telecoms, telekom's, millicom's, omnicom's, sitcoms, telecom's, telecoms, telekom's, guilliams, iams, millicom's, omnicom's, pompoms, sitcoms, telecom's, telecoms, telekom's
Viacom's sounds like:
vacancies, vacancy, vaccine's, vaccines, vacuuming, vacuums, vagueness, vashinsky, vaughan's, vaughn's, vaughns, vegans, vegisnax, vexing, vicencio, vicenzi, viciousness, vicon's, viking, viking's, vikings, vision's, visions, visnic, voicing, vouching