1. A frequent consequence of data arriving faster than it can be consumed, especially in serial linecommunications. For example, at 9600 baud there is almost exactly one character per millisecond, so if a silo can hold only two characters and the machine takes longer than 2 milliseconds to get to service the interrupt, at least one character will be lost. 2. Also applied to non-serial-I/O communications. "I forgot to pay my electric bill due to mail overrun." "Sorry, I got four phone calls in 3 minutes last night and lost your message to overrun." When thrashing at tasks, the next person to make a request might be told "Overrun!" Compare {firehose syndrome}. 3. More loosely, may refer to a buffer overflow not necessarily related to processing time (as in {overrun screw}). [Jargon File]