To release, to free, to give freedom to.
to connect something to something else.
to connect a cellular smartphone to another personal computer in order to give it access to a hotspot.
to restrict something with a tether.
a strong rope or line that connects a sailor's safety harness to the boat's jackstay
a rope, cable etc. that holds something in place whilst allowing some movement
the limit of one's abilities, resources etc.
The cardinal number three in an old counting system used in Teesdale and Swaledale. (Variant of tethera)