Pneuma (pronounced nü-mə) is the essence or driving force of an individual; their spirit or creative fire.
The word pneuma comes from the ancient Greek πνεῦμα meaning “breath” or “moving air”, “wind”. (Compare to the similar word psyche). In ancient Greek philosphy, pneuma was the active force of life, responsible for regulating the heat and motion of the internal working of the body. It was also the active life force of the Universe, drawn into the body through the breath. Pneuma also references the firey aspect of air (oxygen) as observed when one blows air onto a fire, causing it to flare.
In Biblical translations, the word pneuma is often translated as “sprit”, sometimes referencing the Holy Spirit.
The idea of pneuma as a ghost, demonic entity or other spirits independent of corporeal forms, suggests the relationship between the unseen but felt presence of such a being and the unseen but felt presence of moving air, breath, wind.