The word "grasp" primarily means to understand something mentally or intellectually, especially when it might be complicated or difficult. It can also mean to physically hold something firmly with your hands, or to seize or take hold of something abruptly. For example, you might grasp a concept in a discussion or grasp the handle of a door. Grasping often implies a firm or quick understanding or hold, whether of ideas or objects. It is used both literally (holding something) and figuratively (comprehending or seizing an opportunity).

In summary, "grasp" is about taking hold—either physically or mentally—and it signifies comprehension or control of something.