/bif/ To notify someone of incoming mail. From the BSD utility "biff(1)", which was in turn named after a friendly golden Labrador who used to chase frisbees in the halls at UCB while 4.2BSD was in development (it had a well-known habit of barking whenever the mailman came). No relation to BIFF.
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Nearby terms: Bidouilleurs Sans Argent « bi-endian « BIFF « biff » \big » Big bag of pages » big blue