The Collaborative International Dictionary of English v.0.48:

Spuller \Spul"ler\ (sp[u^]l"l[~e]r), n. [For spooler.] [See
   Spool.]
   One employed to inspect yarn, to see that it is well spun,
   and fit for the loom. [Prov. Eng.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Spooler \Spool"er\ (-[~e]r), n.
   One who, or that which, spools.
   [1913 Webster]

The Free On-line Dictionary of Computing (30 December 2018):

spooler

    Software or hardware to which data is
   spooled and which processes that data (e.g. prints it) in the
   background.

   (1995-03-25)