1. Etymology

The word spirit came into Middle English via Old French esperit. Its source is Latin spīritus, whose original meaning was "breath, breathing" and hence "spirit, soul, courage, vigor";^[1] its ultimate origin is a Proto-Indo-European root *(s)peis.

In Latin, spīritus was distinct from Latin anima, whose etymological meaning was also "breathing" (PIE root *h₂enh₁-),^[2] yet which had taken a slightly different meaning, namely "soul".

Classical Greek also had a similar distinction between "soul" and "spirit", in each case involving again an etymological sense "breathing":^[1]

• psykhē (ψυχή), originally "cold air", hence "breath of life" and "soul"^[1] (PIE root *bhes- "to breathe").^[3]
• pneuma (πνεῦμα) "breath, motile air, spirit", from verb pnéō (πνέω) "to breathe".

A distinction between soul and spirit also developed in the Abrahamic religions: Arabic nafs (نفس) opposite rūḥ (روح); Hebrew neshama (נְשָׁמָה nəšâmâh) or nephesh (נֶ֫פֶשׁ nép̄eš) (in Hebrew neshama comes from the root NŠM or "breath") opposite ruach (רוּחַ rúaħ). (Note, however, that in Semitic just as in Indo-European, this dichotomy has not always been as neat historically as it has come to be taken over a long period of development: Both נֶ֫פֶשׁ (root נפשׁ) and רוּחַ (root רוח), as well as cognate words in various Semitic languages, including Arabic, also preserve meanings involving miscellaneous air phenomena: "breath", "wind", and even "odour".^[4][5][6])

2. Usage

"Spirit" has acquired a number of meanings:

• Christian theology can use the term "Spirit" to refer to the Holy Spirit.
  • Christian Science uses "Spirit" as one of seven synonyms for God, as in: "Principle; Mind; Soul; Spirit; Life; Truth; Love"^[7]
  • Latter Day Saint prophet Joseph Smith Jr. (1805-1844) rejected the concept of spirit as incorporeal or without substance: "There is no such thing as immaterial matter. All spirit is matter, but it is more fine or pure, and can only be discerned by purer eyes."^[8] Regarding the soul, Joseph Smith wrote "And the Gods formed man from the dust of the ground, and took his spirit (that is, the man’s spirit), and put it into him; and breathed into his nostrils the breath of life, and man became a living soul."^[9] Thus, the soul is the combination of a spirit with a body (although most LDS members use "soul" and "spirit" interchangeably). In Mormon scripture, spirits are sometimes referred to as "intelligences".^[10] But other Mormon scriptures teach that God organized the spirits out of a pre-existing substance called "intelligence" or "the light of truth".^[11] While this may seem confusing, compare how a programmer writes an algorithm by organizing lines of logical code. The logic always existed, independent of the programmer, but it is the creator who organizes it into a living spirit / intelligence / soul.
• Various forms of animism, such as Japan's Shinto and African traditional religion, focus on invisible beings that represent or connect with plants, animals, or landforms (in Japanese: kami): translators usually employ the English word "spirit" when trying to express the idea of such entities.^[12] Compare the concepts of ancestral spirits and of spirit animals.
• According to C. G. Jung (in a lecture delivered to the literary Society of Augsburg, 20 October 1926, on the theme of “Nature and Spirit”):

The connection between spirit and life is one of those problems involving factors of such complexity that we have to be on our guard lest we ourselves get caught in the net of words in which we seek to ensnare these great enigmas. For how can we bring into the orbit of our thought those limitless complexities of life which we call "Spirit" or "Life" unless we clothe them in verbal concepts, themselves mere counters of the intellect? The mistrust of verbal concepts, inconvenient as it is, nevertheless seems to me to be very much in place in speaking of fundamentals. "Spirit" and "Life" are familiar enough words to us, very old acquaintances in fact, pawns that for thousands of years have been pushed back and forth on the thinker's chessboard. The problem must have begun in the grey dawn of time, when someone made the bewildering discovery that the living breath which left the body of the dying man in the last death-rattle meant more than just air in motion. It can scarcely be an accident onomatopoeic words like ruach (Hebrew), ruch (Arabic), roho (Swahili) mean 'spirit' no less clearly than πνεύμα (pneuma, Greek) and spiritus (Latin).^[13]

• Psychical research, "In all the publications of the Society for Psychical Research the term 'spirit' stands for the personal stream of consciousness whatever else it may ultimately be proved to imply or require" (James H. Hyslop, 1919).^[14]
• Paranormal spirits: usually a nickname for a ghost or other undead spirit.

3. Related Concepts

Similar concepts in other languages include Greek pneuma, Chinese Ling and hun (靈魂) and Sanskrit akasha / atman^[1] (see also prana). Some languages use a word for spirit often closely related (if not synonymous) to mind. Examples include the German Geist (related to the English word ghost) or the French l'esprit.^[15] English versions of the Bible most commonly translate the Hebrew word ruach (רוח; wind) as "the spirit."^[16]

Alternatively, Hebrew texts commonly use the word nephesh. Kabbalists regard nephesh as one of the five parts of the Jewish soul, where nephesh (animal) refers to the physical being and its animal instincts. Similarly, Scandinavian, Baltic, and Slavic languages, as well as Chinese (气 qi), use the words for breath to express concepts similar to "the spirit".^[1]