1. Air or an all-pervading fiery essence in the air (which today would be identified with oxygen), which was the creative and animating spirit of the universe; drawn into the body through the lungs, it generated and sustained the innate heat in the left ventricle of the heart and was distributed by the arteries to the brain and all parts of the body.
2. Soul or psyche.
The information shown above for pneuma is provided by Stedman's.
* Stedman's, part of Lippincott Williams & Wilkins, provide a comprehensive line of health-science publications for healthcare professionals and medical students.