The terms used in TCM are much different than Western medical terms. For example, the channels of acupuncture points on the body are comparable to streams, rivers, and the sea. When the water flows freely, everything is in harmony. If something blocks the flow of water, it stagnates or is forced into another path. Similarly if the Qi in the channels flows freely, there is harmony. Although, if something disrupts this free flow, this manifests as pain or organ disharmony.
Basic terms used in TCM diagnosis include yin and yang. These two terms describe the inter-relatedness and inter-dependence of opposing forces. The characteristics of yin and yang can be compared in the following chart: