I. teth ‧ er 1 /ˈteðə $ -ər/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old Norse ; Origin: tjothr ]
1 . be at the end of your tether to be so worried, tired etc that you feel you can no longer deal with a difficult or upsetting situation
2 . a rope or chain that an animal is tied to so that it can only move around within a limited area
II. tether 2 BrE AmE verb [transitive]
to tie an animal to a post so that it can only move around within a limited area