any cylindrical piece or device on which something is wound.
a small cylindrical piece of wood or other material on which yarn is wound in spinning, for use in weaving; a bobbin.
a small cylinder of wood or other material on which thread, wire, or tape is wound, typically expanded or with a rim at each end and having a hole lengthwise through the center.
the material or quantity of material wound on such a device.
the cylindrical drum in a reel that bears the line.
—v.t.
to wind on a spool.
to unwind from a spool (usually fol. by off or out).
to operate (an input/output device) by using buffers in main and secondary storage.