PIE*kenk、膝の曲げ伸ばし、かかと、語源的には踵と同じ。
hock 質、抵当オランダ語の hok, 刑務所、フェンス、犬小屋から。オランダ語のhok、牢獄、フェンス、犬小屋から。 借金から派生し、後に質、抵当権の意味に使われる。
When one gambler is caught by another, smarter than himself, and is beat, then he is in hock. Men are only caught, or put in hock, on the race-tracks, or on the steamboats down South. ... Among thieves a man is in hock when he is in prison. [G.W. Matsell, "Vocabulum," 1859]