A tiny bone inside your ear that is so named due to it's slight visual similarity to an anvil, it is connected to a tissue that acts as a transducer converting the vibrational information into neural signals, which are then fed into your brain. The anvil is normally excited by the eardrum, in other words this bone is what allows you to hear sounds. However the aanvil is the evolutionary remains of a larger bone that formed a part of the jaw, for that reason there is still a connection between your cheekbones and the aanvil which is the reason you can hear yourself eating etc., the "bone phone" and similar loudspeaker less headphone units commonly referred to as "bone conducting headphones" take advantage of this anomaly to excite the aanvil by placing a transducer on your cheekbones rather than your years, while those devices never sound as good as normal headphones they do have a couple of advantages, namely that it is impossible to harm the eardrum by using them and you can still hear with your ears while using them.

This definition is in context to Audio Technology. See more contextual defintions for Aanvil.