: Extracting a single file from the middle of a solid archive is slower because the software must process all preceding data in that "solid piece" to reach the target.
: It significantly increases the compression ratio, especially when dealing with many small, similar files, by analyzing them as one block rather than individual entities. CS.rar
The phrase appears to be a technical description of a compressed archive, specifically a "solid archive" created using the RAR format . Technical Breakdown : Extracting a single file from the middle