Meridians are energy pathways that run through out the body. If you want to conceptualize them they are similar to our circulatory system or nervous system.
Each meridian is connected to a different organ. (Ie, Kidney, heart, liver, etc.) Most of the acupuncture points are located on these meridian pathways.
When we instruct you to use essential oils on an acupuncture point we always tell you to rub before and after the point. This is to further stimulate more of the meridian for some extra help for that organ.