gripper
Something that holds things tightly, like a tool or part.
A gripper is something that grips or holds onto things firmly. The rubber bottom of your sneakers acts as a gripper, keeping you from slipping on smooth floors. A jar opener with textured rubber is a gripper that helps you twist stubborn lids. Rock climbers wear special shoes with grippy rubber soles that work like powerful grippers on tiny ledges.
In robotics and manufacturing, grippers are mechanical hands or claws that grab and move objects. A robot gripper in a car factory might pick up heavy engine parts and place them precisely where they need to go. These grippers can be surprisingly gentle too: some can grip a raw egg without cracking it, while others can lift hundreds of pounds.
The word can also describe someone with an especially strong grip. A gymnast might have the hands of a real gripper, able to hang from a bar for minutes without letting go.
Some people also call really engaging books or movies grippers because they grab your attention and won't let go, though page-turner or nail-biter are more common ways to express that idea.