Origin of intro
- L intro- < intro, inwardly, on the inside < *intero, akin to inter: see inter-
From Webster's New World College Dictionary, 5th Edition
- Latin intrō- from intrō to the inside en in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- Abbreviated from introduction, from Latin, ultimately a compound from intrō (“I enter”) – the abbreviation removes the second part of the compound, 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.