All 3 Uses

tether
in
Equus
(Auto-generated)

For a moment they seem to converge on the boy as he stands in the middle of the stable, but then they swiftly turn and take up positions as if tethered by the head, with their invisible rumps towards him, one by each bench.†
Scene 1.16 *

tethered = tied so as to limit the boundaries of movement
When that's done, I'll set him on a nice mini-scooter and send him puttering off into the Normal world where animals are treated properly: made extinct, or put into servitude, or tethered all their lives in dim light, just to feed it!†
Scene 2.35
I'll give him the good Normal world where we're tethered beside them—blinking our nights away in a non-stop drench of cathode-ray over our shrivelling heads!†
Scene 2.35

Definitions:

(1) (tether)
to tie so as to limit the boundaries of movement; or the rope or other material used to do the tying
(2) (meaning too rare to warrant focus)