Boyd’s Bible Dictionary:
(hok) (hock). Cutting the sinews of the hind, leg, hamstringing (Josh. 11:6,9; 2 Sam. 8:4).
Concise Bible Dictionary:
To lame a horse and render it useless by cutting the sinews of the hind leg, called the hamstring (Josh. 11:6,9; 2 Sam. 8:4; 1 Chron. 18:4).