Gwasanaeth S4C i’r plant ifancaf yw Cyw. Ymunwch â byd hudol Cyw drwy gwrdd â’r cymeriadau, darllen straeon, chwarae gemau a dysgu caneuon.–Cyw is S4C’s service for the youngest children. Become part of Cyw’s magical world, meet the characters, have fun reading stories, play games and learn songs.–Keywords / Geiriau allweddol: Cyw, watch, song, songs, eLyfr, eBook, e book, S4C, Gem, Games, Caneuon, Cân, Cymraeg, Welsh, Cymru, Wales.