In spiritualism, ectoplasm, also known as simply ecto, a substance or spiritual energy "exteriorized" by physical mediums. It was coined in 1894 by psychical researcher Charles Richet. Although the term is widespread in popular culture, there is no scientific evidence that ectoplasm exists and many purported examples were exposed as hoaxes fashioned from cheesecloth, gauze or other natural substances.

Spiritualism is a social religious movement primarily popular in the nineteenth and early twentieth centuries according to which an individual's awareness persists after death and may be contacted by the living. The afterlife, or the "spirit world", is seen by spiritualists not as a static place, but as one in which spirits continue to evolve. These two beliefs—that contact with spirits is possible, and that spirits are more advanced than humans—lead spiritualists to the belief that spirits are capable of providing useful insight regarding moral and ethical issues, as well as about the nature of God. Some spiritualists speak of a concept which they refer to as "spirit guides"—specific spirits, often contacted, who are relied upon for spiritual guidance. Emanuel Swedenborg has some claim to be the father of spiritualism.