interstitial

1. (Internet, advertising) A web page, usually carrying advertising, displayed when leaving one content page for another.Examples: "An interstitial appeared before the download."; "Interstitials should be used sparingly. Display an ad only the first time the user accesses a piece of content, not every time."Internet

2. (physics) An interstitial discontinuity in a crystal.Examples: "2008, E. G. Seebauer et al., Defect Engineering for Ultrashallow Junctions using Surfaces, in P. J. Timans, E. P. Gusev, H. Iwai, D.-L. Kwong, M. C. Öztürk, F. Roozeboom (editors), Advanced Gate Stack, Source/Drain, and Channel Engineering for Si-Based CMOS 4: New Materials, Processes, and Equipment, ECS Transactions: Volume 13, Issue 1, page 56, The second mechanism, which is the primary focus of the present paper, involves insertion of interstitials into dangling bonds at the surface."