preroll
n.— «Monday, Hurley, one of YouTube’s founders, appeared more open to experimenting, saying he was even considering testing what’s known as a “preroll”—showing a 15-second ad before a clip—something he had long derided as potentially ruining the user experience.» —“1 1/2-year-old YouTube sold to Google for $1.65 billion” by Andrew Ross Sorkin Seattle Post-Intelligencer (Washington) Oct. 10, 2006. (source: Double-Tongued Dictionary)