Equilibrioception

Equilibrioception is the sense of balance. This is what prevents a person or animal from falling over while walking or doing other physical activity.
In humans.
In humans, equilibrioception is mainly sensed by the detection of acceleration, which occurs in the vestibular system. Other senses play roles as well, e.g. the visual system and proprioception. The importance of visual input for balance is illustrated by its being harder to stand on one foot with eyes closed than with eyes open.
The sense of balance often gets worse as a person ages. After a stroke, it may be improved with the help of special training.