Definition of "spool"

A reel; a device around which thread, wire or cable is wound, especially a cylinder or spindle.  quotations  examples

(aviation) One of the rotating assemblies of a gas turbine engine, composed of one or more turbine stages, a shaft, and one or more compressor or fan stages.  examples

(computing) A temporary storage area for electronic mail, etc.  examples

To wind on a spool or spools.  examples

(computing) To send files to a device or a program (a spooler or a daemon that puts them in a queue for processing at a later time).  examples

A small swimming pool that can be used also as a spa.  examples