Co je tether? Co je tether? A rope, chain, or similar restraint for holding an animal in place, allowing a short radius in which it can move about.A similar ropelike restraint used as a safety measure, especially for young children and astronauts.A rope, chain, or similar restraint for holding one, especially an animal, in place, allowing a short radius in which one can move about.The extent or limit of one's resources, abilities, or endurance: drought-stricken farmers at the end of their tether. To fasten or restrict with or as if with a tether.