[from early IBM `Simultaneous Peripheral Operation On-Line', but this acronym is widely thought to have been contrived for effect] vt. To send files to some device or program (a `spooler') that queues them up and does something useful with them later. The spooler usually understood is the `print spooler' controlling output of jobs to a printer, but the term has been used in connection with other peripherals (especially plotters and graphics devices) and occasionally even for input devices. See also demon.