Spirit (n.) c.1250, "animating or vital principle in man and animals," from O.Fr. espirit, from L. spiritus "soul, courage, vigor, breath," related to spirare "to breathe," from PIE *(s)peis- "to blow" (cf. O.C.S. pisto "to play on the flute"). Original usage in Eng. mainly from passages in Vulgate, where the L. word translates Gk. pneuma and Heb. ruach. Distinction between "soul" and "spirit" (as "seat of emotions") became current in Christian terminology (e.g. Gk. psykhe vs. pneuma, L. anima vs. spiritus) but "is without significance for earlier periods" [Buck]. L. spiritus, usually in classical L. "breath," replaces animus in the sense "spirit" in the imperial period and appears in Christian writings as the usual equivalent of Gk. pneuma. Meaning "supernatural being" is attested from c.1300 (see ghost); that of "essential principle of something" (in a non-theological sense, e.g. Spirit of St. Louis) is attested from 1690, common after 1800. Plural form spirits "volatile substance" is an alchemical idea, first attested 1610; sense narrowed to "strong alcoholic liquor" by 1678. This also is the sense in spirit level (1768). Etymology online

Pneuma πνευμα is Greek for "breath", which metaphorically describes a non-material being or influence.

Synonyms are; anima, anima humana, animating force, animus, atman, ba, bathmism, beating heart, biological clock, biorhythm, blood, breath, breath of life, buddhi, divine breath, divine spark, ego, elan vital, essence of life, force of life, growth force, heart, heartbeat, heartblood, impulse of life, inner man, inspiriting force, jiva, jivatma, khu, life breath, life cycle, life essence, life force, life principle, life process, lifeblood, living force, manes, mind, nephesh, prana, psyche, purusha, ruach, seat of life, shade, shadow, soul, spark of life, spirit, spiritual being, spiritus, the self, vis vitae, vis vitalis, vital energy, vital flame, vital fluid, vital force, vital principle, vital spark, vital spirit. (Moby Thessaurus).

Spirit, Ruach or Pneuma is an energy.

An, was born in this dimension; Nammu, the primal water, as the twin Ki-An; Earth and Spirit, indicating that they are two sides of the same coin. This spiritual Light is shone into our dimension by God the Father from his own dimension; his own heaven and because of this, this emanation is called the Son; our spiritual Sun. 

It is because of this that anyone who's soul is fully enlightened by this Light is called a son of God, and it the reason that God is called Father or even Grandfather.  In India God originally was known as Brahma; Ab Rama; the Father from above.

Rakefet encyclopedic theosophical glossary says: Spirit Cosmically, the homogeneous emanation from the universal cosmic monad; in man, the direct emanation of his spiritual monad, the immortal element in us which never was born and which retains through the mahamanvantara its own quality, essence, and characteristics. It sends its ray through the laya-centers of all the various sheaths of consciousness-substance, and is itself a ray of the all-spirit is used specifically for the union of the higher part of manas with atma-buddhi.

"The lack of any mutual agreement between writers in the use of this word has resulted in dire confusion. It is commonly made synonymous with soul; and the lexicographers countenance the usage. In Theosophical teachings the term 'Spirit' is applied solely to that which belongs directly to Universal Consciousness, and which is its homogeneous and unadulterated emanation. ..... In many languages the same word means both spirit and breath or wind; spirit is related to air among the subtle cosmic elements (maha-tattvas or mahabhutas). Spirit, considered as the cosmic Ens (being) or Brahman is not the cosmic primordial root, but its first manifestation, corresponding to the Greek First Logos -- either parabrahman-mulaprakriti, when applied to the galaxy; or Brahman-pradhana when applied to our solar system. Although of a wide and general use, in theosophy it means incorporeal intelligences of a high degree, such as dyanis or planetary spirits, those hosts of arupa (bodiless) monads or egos which spring more or less directly from the universal consciousness or cosmic spirit. Thus the spiritual monad in man is, strictly speaking, a spirit as derivative directly from the cosmic intelligence, mahat or mahabuddhi manifesting through mahat. Spirits exist in almost limitless ranges of hierarchical classes, highest, intermediate, and lower. A great distinction is drawn between spirit and soul, the vehicle of an ego. Theosophy objects to its use for astral kama-rupas of the seance room.

Which all still sounds really complicated.