Fish hooks are pointed and barbed at one end to aid in catching fish.
A grappling hook has multiple hooks from a central anchor, to increase the chances of catching a part of a surface that the hook can hold.
A hook-and-eye clasp is composed of two pieces that are sewn to clothing, for which one is able to hook around the other.
A hook is a tool consisting of a length of material that contains a portion that is curved or indented, so that this portion can be used to hold another object. In a number of uses, one end of the hook is pointed, so that this end can pierce another material, which is then held by the curved or indented portion.