'ectoplasm' originates from Neo-Latin, formed from the Greek elements 'ektos' meaning 'outside' and 'plasma' meaning 'something formed' or 'molded'.

'ectoplasm' was coined in scientific usage in the late 19th century (from Neo-Latin 'ectoplasm'), using Greek roots; it entered English directly in that scientific sense and later gained a secondary usage in paranormal literature.

Initially it referred specifically to the outer layer of cytoplasm in protozoa and similar organisms; in the early 20th century the term was extended in spiritualist and paranormal contexts to denote a purported material produced by spirits or mediums.