The English word "spirit" comes from the Latin "spiritus" (breath). The term is commonly used to refer to a supernatural being which is transcendent and therefore metaphysical in nature. For many people, however, spirit, like soul, is a natural part of a being, and is identified with mind, or consciousness, or the brain.

Etymology

The English word "spirit" comes from the Latin spiritus, meaning "breath" (compare spiritus asper), but also "soul, courage, vigor", ultimately from a PIE root *(s)peis- (to blow). In the Vulgate, the Latin word translates Greek (πνευμα), pneuma (Hebrew (רוח) ruah), as opposed to anima, translating psykhē. The word was loaned into Middle English via Old French The distinction between soul and spirit became current in Judeo-Christian terminology (e.g. Greek. psykhe vs. pneuma, Latin anima vs. spiritus, Hebrew ruach vs. neshama or nephesh; in Hebrew neshama from the root NSHM or breath.)

Metaphysical and metaphorical uses

The word is used in two related contexts, one metaphysical and the other metaphorical.

Its metaphysical context has attained a number of meanings:

1. An incorporeal but ubiquitous, non-quantifiable substance or energy present individually in all living things. Unlike the concept of souls, which are by definition eternal and usually believed to preexist the body, a spirit develops and grows as an integral aspect of the living being. This concept of the individual spirit is common among traditional peoples. It is therefore important to note the distinction between this concept of spirit and that of the pre-existing or eternal soul because belief in souls is specific and far less common, particularly in traditional societies. This is more properly termed life ("bios" in Greek) ether than spirit ("pneuma" in Greek.)
2. A daemon sprite, or especially ghost. A ghost is usually conceived as a wandering spirit from a being no longer living, having survived the death of the body yet maintaining the mind and consciousness.
3. In religion and spirituality, the respiration of the human being has for obvious reasons been strongly linked with the very occurrence of life. A similar significance has been attributed to human blood. Spirit in this sense denotes that which separates a living body from a corpse and usually implies intelligence, consciousness and sentience.
4. Various animistic religions, such as Japan's Shinto and various Native American and African tribal beliefs, focus around invisible beings which represent or are connected to plants, animals (sometimes called Animal Fathers), or even landforms; the English word "spirit" is usually used when translating tales related to such entities.
5. Spirits are often visualized as being interconnected to all others and The Spirit (singular capitalized) refers to the theories of a unified spirituality, universal consciousness and some concepts of Deity. All "spirits" connected, form a greater unity, the Spirit, which has both an identity separate from its elements plus a consciousness and intellect greater than its elements; an ultimate, unified, non-dual awareness or force of life combining or transcending all individual units of consciousness. The experience of such a connection can be a primary basis for spiritual belief. The term spirit has been used in this sense by at least Anthroposophy, Aurobindo, A Course In Miracles, Hegel, and Ken Wilber. In this use, the term is conceptually identical to Plotinus's "One" and Friedrich Schelling's "Absolute." Similarly, according to the pan(en)theistic aspect, Spirit is the essence that can manifest itself as mind/soul through any level in pantheistic hierarchy/holarchy, such as a mind/soul of a single cell (with very primitive, elemental consciousness), or a human or animal mind/soul (with consciousness on a level of organic synergy of an individual human/animal), or a (superior) mind/soul with synergetically extremely complex/sophisticated consciousness of whole galaxies involving all sub-levels, all emanating (since it is non-dimensional, or trans-dimensional) from the one Spirit.
6. In Christian theology, the Spirit is also used to describe God, or aspects thereof as in Holy Spirit, referring to a Triune God (Trinity): "The result of God reaching to man by the Father as the source, the Son as the course ("the Way"), and through the Spirit as the transmission."
7. Also in (popular) theological terms, the individual human "spirit" (singular lowercase) is a deeply situated aspect of the soul subject to "spiritual" growth and change; the very seat of emotion and desire, and the transmitting organ by which human beings can contact God. In a rare theological definition it is higher consciousness enclosing the soul. It is a central concept of Pneumatology (in context of the latter definition note that this science studies "pneuma;" Greek for "spirit," not "psyche;" Greek for "soul" studied in psychology.
8. In Christian Science, Spirit is one of the seven synonyms for God. These are: "Principle; Mind; Soul; Spirit; Life; Truth; Love" (Science and Health with Key to the Scriptures by Mary Baker Eddy, p. 587).
9. In Harmonism, spirit is a term reserved for those which collectively control and influence an individual from the realm of the mind.