The terms biao li may be translated as outer and inner, exterior and interior, and they must be differentiated from the similar terms nei (內) and wai (外). In medicine biao/li is often used to indicate a movement of qi, which is either yin (towards the interior) or yang (towards the exterior).
The etymology of the characters can be seen in the radical they both share – that for cloth or clothing (衣). The biao (表) of a garment is its external outer appearance, the li (裏) its lining, or hidden aspect. The biao faces towards the exterior and can be seen, the li faces towards the inner and cannot be seen. Biao can also mean to be manifest, and the interesting interplay of these two characters expresses the way in which inner qualities and conditions can manifest themselves at the exterior – a very important aspect of diagnosis. Read more