Meaning

noun formally making a person known to another or to the public

noun a brief introductory passage to a piece of popular music

originClipping of introduction, from Latin intrōductiō (“lead-in, introduction”) – the abbreviation removes the second part of the compound; the first part ultimately from Proto-Indo-European *h₁énteros (“inner, what is inside”). The demoscene sense comes from the fact that they were originally prepended to pirated copies of computer games.

Etymology from Wiktionary, CC BY-SA 3.0