What "crack" means in rock climbing

In rock climbing, "crack" refers to a natural crevice or fissure in the rock that one can use to hold onto or place gear. Climbers can wedge their hands, fingers, or even entire arms into the crack to find secure holds and progress upward. Crack climbing is considered a specialty in rock climbing and requires a specific set of techniques and gear, such as camming devices and nuts, to safely climb up the crack without falling.