To kneel on one knee and then rise as an act of respect.
Pilgrims in China not only genuflect before religious shrines but also may lay themselves flat on the ground and light incense as well.
Genuflection, which contains the root genu-, "knee," has long been a mark of respect and obedience. King Arthur's Knights of the Round Table genuflected not only when he knighted them but whenever they greeted him formally. This custom remains in countries today that are still ruled by royalty, and in some churches each worshiper is expected to genuflect whenever entering or leaving a pew on the central aisle. By genuflecting you show loyalty to a human or god and admit your duty to obey his or her orders.