jam track
n.— «These give you access to set of intermediate lessons and “jam tracks” which serve as background loops for you to practice what you’ve learned.» —“Learn how to play guitar in your browser (in 3D)” by Josh Lowensohn CNET: The Download Blog Jan. 8, 2009. (source: Double-Tongued Dictionary)
You missed a good one in this article… ‘webmercial’… arguably a more important citation, IMHO…