In religion and philosophy, spirit is the vital principle or animating essence within humans or, in some views, all living things. Although views of spirit vary between different belief systems, when spirit is contrasted with the soul, the former is often seen as a basic natural force, principle or substance, whereas the latter is used to describe the organized structure of an individual being's consciousness, in humans to include their personality. Spirit as a substance may also be contrasted with matter, where it is usually seen as more subtle, an idea put forth for example in the Principia Mathematica.
Etymology
The word spirit came into Middle English via Old French . Its source is Latin , whose original meaning was "breath, breathing" and hence "spirit, soul, courage, vigor"; its ultimate origin is a Proto-Indo-European root *(s)peis-.
In Latin, was distinct from Latin , whose etymological meaning was also "breathing" (PIE root ), yet which had taken a slightly different meaning, namely "soul".
The distinction between "soul" and "spirit" in English mirrors that between "" and "" in Classical Greek, with both words having a connection to breathing:
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|   ||   || originally "cold air", hence "breath of life" and "soul" English versions of the Bible most commonly translate the Hebrew word (; wind) as "the spirit".
A distinction between soul and spirit developed in Arabic and Hebrew: Arabic () opposite (); and Hebrew ( ) or ( ) (in Hebrew, comes from the root or "breath") opposite ( ). (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 (root ) and (root ), as well as cognate words in various Semitic languages, including Arabic, also preserve meanings involving miscellaneous air phenomena: "breath", "wind", and even "odour".)
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 use the words for breath to express concepts similar to "the spirit".
Christianity
The Christian New Testament uses the term pneuma to refer to "spirit", "spiritual" and specifically to the Holy Spirit. The relationship between the Holy Spirit in Christianity and spirit in other religions is unclear. The distinction between psyche and pneuma may be borrowed from the Hellenistic religions through Hellenistic Jews such as Philo, a view held by the so-called History of religions school.
However, others think that the Holy Spirit may actually resemble the Stoic concept of the anima mundi, or world soul, more than the pneuma. According to theologian Erik Konsmo, there is no relationship between the pneuma in Greek philosophy and the pneuma in Christianity beyond the use of the word itself.