teth·er 
(tĕ-=…|th=-ər)
(tĕ-=…|th=-ər)n.
1.
a. A rope, chain, strap, or cord for keeping an animal within a certain radius.
b. A similar ropelike restraint used as a safety measure, as for a young child or an astronaut outside a spacecraft.
c. A rope, chain, cable, or other line for restraining or securing an object: a blimp attached to the ground by tethers.
2. The extent or limit of one's resources, abilities, or endurance: drought-stricken farmers at the end of their tether.
3. A range of allowable behavior or responsibility: kept the new assistant on a short tether.
tr.v. teth·ered, teth·er·ing, teth·ers
To restrain or secure with a tether.
[Middle English teder, from Old Norse tjōdhr.]