A spool may refer to any of the following:
1. Short for Simultaneous peripheral operations online, spool is often used to describe a task such as a print job. See the print spool definition for further information.
2. Spool was also a large reel of 1/2-inch-wide magnetic tape used with old mainframe computers.
3. Alternatively referred to as a mail spool or spool file, a spool is a temporary location or name of the directory some e-mail services use to store e-mail until the client retrieve it.
4. Alternatively referred to as a news spool the spool is a temporary location to store Usenet articles.
5. See the spooling dictionary definition for other related terms.