Very simply it stands for over the air and with an indoor antenna like the Leaf Antenna, you can tune into a free television signal, rather than having to connect to a cable box using coaxial cables. An OTA antenna is what people used to use back in the golden age of television, before there was anything like a coaxial cable, and when there were three or four channels at the most. OTA channels still very much exist and with the OTA update that was made when it became clear that HD was here to stay, you can now get HDTV antennas and watch those major channels with a crystal clear picture, without befooing tied down to a cable provider. If you want to learn more about Indoor Antennas and how to get major network channels for free in HD come find us at KilltheCableBill.