Put simply, balance is the ability to minimise or negate forces acting upon your body which have the potential to disrupt equilibrium.
These forces may be internal – such as tight muscles or a poorly functioning vestibular (inner ear) system.
They may be external – such as your partner or an uneven floor. Even a dark room or flashing disco lights can affect balance on a busy dance floor as your brain will inhibit movement when it is less able to predict safe outcomes.
A large part of any dance technique is learning to overcome these factors so good quality movement becomes automatic, and you can focus more concious effort towards musical interpretation and improvisation.