The "hook" is a fish hook.

“钩”在这里指的是鱼钩。

youdao

A fish hook has a barb to prevent the fish from escaping after being hooked.

鱼钩上都有一个倒钩以防上了钩的鱼逃走。

youdao

The boss took two steps back and asked in astonishment, "You sold all that to a guy who came in for a fish hook?"

老板后退两步，几乎难以置信地问道：“一个顾客仅仅来买个鱼钩，你就能卖给他这么多东西？”

youdao

Jeff Peters and Andy Tucker were now ready to catch a few fish on the hook.

VOA: special.2010.04.24

Edison would go fishing in the middle of a workday at a nearby pond, and he would fish with a baitless hook.

FORBES: Investing Lessons From Da Vinci And Edison

It took me four hours to hook a fish and 40 minutes to reel him in.

WSJ: Learning to Fly Fish��And Fend Off the Grizzlies | Traveler's Tale

In March he will likely head to fish the saltwater flats in Florida for bonefish and tarpon and perhaps permit (a species of fish that has thus far eluded his hook).

FORBES: Gone Fishing: Paul Volcker Retires From Public Life, Heads For the River