"Bilateral coordination" is the ability to use both sides of the body at the same time in a controlled and organized manner.
This can mean using both sides to:
Play a musical instrument
Use scissors to cut out shapes
Throw or catch a ball
Push and pull toys
Being able to coordinate both sides of the body in a controlled and organized way indicates that both sides of the brain are communicating and sharing information with each other. Having good bilateral coordination allows the hands and feet to work well together.