The meaning of spirituality has developed and expanded over time, and various meanings can be found alongside each other. Traditionally, spirituality referred to a religious process of re-formation which "aims to recover the original shape of man", oriented at "the image of God" as exemplified by the founders and sacred texts of the religions of the world. The term was used within early Christianity to refer to a life oriented toward the Holy Spirit and broadened during the Late Middle Ages to include mental aspects of life.

In modern times, the term has spread to other religious traditions. It broadened to refer to a wider range of experiences, including a range of esoteric and religious traditions. Modern usages tend to refer to a subjective experience of a sacred dimension, and the "deepest values and meanings by which people live", often in a context separate from organized religious institutions. This may involve belief in a supernatural realm beyond the ordinarily observable world, personal growth, a quest for an ultimate or sacred meaning, religious experience, or an encounter with one's own "inner dimension" or spirit.

The term spirit means "animating or vital principle in man and animals". It is derived from the Old French espirit, which comes from the Latin word spiritus (soul, ghost, courage, vigor, breath) and is related to spirare (to breathe). In the Vulgate, the Latin word spiritus is used to translate the Greek pneuma and Hebrew ruach.

The term "spiritual", meaning "concerning the spirit", is derived from Old French spirituel (12c.), which is derived from Latin spiritualis, which comes by spiritus or "spirit".

The term "spirituality" is derived from Middle French spiritualité, from Late Latin spiritualitatem (nominative spiritualitas), which is also derived from Latin spiritualis.

There is no single, widely agreed-upon definition of spirituality. Surveys of the definition of the term, as used in scholarly research, show a broad range of definitions with limited overlap. A survey of reviews by McCarroll, each dealing with the topic of spirituality, gave twenty-seven explicit definitions among which "there was little agreement". This causes some difficulty in trying to study spirituality systematically; i.e., it impedes both understanding and the capacity to communicate findings in a meaningful fashion.

According to Kees Waaijman, the traditional meaning of spirituality is a process of re-formation that "aims to recover the original shape of man, the image of God. To accomplish this, the re-formation is oriented at a mold, which represents the original shape: in Judaism the Torah, in Christianity there is Christ, for Buddhism, Buddha, and in Islam, Muhammad." Houtman and Aupers suggest that modern spirituality is a blend of humanistic psychology, mystical and esoteric traditions, and Eastern religions.

In modern times the emphasis is on subjective experience and the "deepest values and meanings by which people live", incorporating personal growth or transformation, usually in a context separate from organized religious institutions. Spirituality can be defined generally as an individual's search for ultimate or sacred meaning, and purpose in life. Additionally it can mean to seek out or search for personal growth, religious experience, belief in a supernatural realm or afterlife, or to make sense of one's own "inner dimension".