Which part of a compass is specifically designed to secure the compass and assist in aiming?

The part of a compass specifically designed to secure the compass and assist in aiming is the thumb loop. This component allows the user to stabilize the compass securely in their hand, ensuring that it remains steady while taking bearings. By using the thumb loop, an individual can effectively align the compass with their line of sight, which is crucial for accurate navigation. The design of the thumb loop enhances user control and improves the overall precision of readings taken with the compass.

In contrast, the lens primarily serves to magnify the compass dial, aiding in the reading of measurements but not in stabilization or aiming. The compass dial itself is the component that displays the cardinal directions and bearings but does not provide physical support or a mechanism for holding the compass. The option "Buy with confidence" does not relate to the function of a compass at all. Thus, the thumb loop is crucial for effective compass use, combining grip and aiming accuracy.