An overbite refers to a large horizontal overlap of the upper front teeth over the lower front teeth.
If your finger can fit between the upper and lower front teeth, it is more than likely you have an overbite. With a large overbite, the front teeth appear to stick out as it is difficult to close the lips naturally.
An overbite may also be referred to as a jaw overbite. This is often due to a smaller lower jaw. The jaw problems are best to be managed early while your child is growing, for this is the time the jaw growth can be easily redirected, resulting a healthier teeth, a more balanced bite and facial harmony.