1. A computer; esp. in the construction `foo box' where foo is some functional qualifier, like `graphics', or the name of an OS (thus, `Unix box', `MS-DOS box', etc.) "We preprocess the data on Unix boxes before handing it up to the mainframe." 2. [IBM] Without qualification but within an SNA-using site, this refers specifically to an IBM front-end processor or FEP /F-E-P/. An FEP is a small computer necessary to enable an IBM mainframe to communicate beyond the limits of the dinosaur pen. Typically used in expressions like the cry that goes up when an SNA network goes down: "Looks like the box has fallen over." (See fall over.) See also IBM, fear and loathing, Blue Glue.