The Collaborative International Dictionary of English v.0.48:

Daemon \D[ae]"mon\, n., Daemonic \D[ae]*mon"ic\, a.
   See Demon, Demonic.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Demon \De"mon\, n. [F. d['e]mon, L. daemon a spirit, an evil
   spirit, fr. Gr. dai`mwn a divinity; of uncertain origin.]
   1. (Gr. Antiq.) A spirit, or immaterial being, holding a
      middle place between men and deities in pagan mythology.
      [1913 Webster]

            The demon kind is of an intermediate nature between
            the divine and the human.             --Sydenham.
      [1913 Webster]

   2. One's genius; a tutelary spirit or internal voice; as, the
      demon of Socrates. [Often written d[ae]mon.]
      [1913 Webster]

   3. An evil spirit; a devil.
      [1913 Webster]

            That same demon that hath gulled thee thus. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

daemon
    n 1: an evil supernatural being [syn: devil, fiend, demon,
         daemon, daimon]
    2: a person who is part mortal and part god [syn: daemon,
       demigod]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "daemon":
   Geist, Muse, afflatus, ancestral spirits, angel, attendant godling,
   atua, control, creative thought, creativity, daimonion, demon,
   divine afflatus, evil spirits, fairy godmother, familiar,
   familiar spirit, fire of genius, genius, genius domus, genius loci,
   good angel, good genius, guardian, guardian angel, guardian spirit,
   guide, household gods, inspiration, intelligence, invisible helper,
   lares and penates, lares compitales, lares familiaris,
   lares permarini, lares praestites, lares viales, manes,
   ministering angel, numen, penates, soul, special providence,
   specter, spirit, supernatural being, talent, totem, tutelar god,
   tutelary



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DAEMON
       Disk And Execution MONitor (Unix)


The Jargon File (version 4.4.7, 29 Dec 2003):

daemon
 /day'mn/, /dee?mn/, n.

    [from Maxwell's Demon, later incorrectly retronymed as ?Disk And Execution
    MONitor?] A program that is not invoked explicitly, but lies dormant
    waiting for some condition(s) to occur. The idea is that the perpetrator of
    the condition need not be aware that a daemon is lurking (though often a
    program will commit an action only because it knows that it will implicitly
    invoke a daemon). For example, under ITS, writing a file on the LPT
    spooler's directory would invoke the spooling daemon, which would then
    print the file. The advantage is that programs wanting (in this example)
    files printed need neither compete for access to nor understand any
    idiosyncrasies of the LPT. They simply enter their implicit requests and
    let the daemon decide what to do with them. Daemons are usually spawned
    automatically by the system, and may either live forever or be regenerated
    at intervals.

    Daemon and demon are often used interchangeably, but seem to have
    distinct connotations. The term daemon was introduced to computing by CTSS
     people (who pronounced it /dee'mon/) and used it to refer to what ITS
    called a dragon; the prototype was a program called DAEMON that
    automatically made tape backups of the file system. Although the meaning
    and the pronunciation have drifted, we think this glossary reflects current
    (2003) usage.


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

daemon

    /day'mn/ or /dee'mn/ (From the mythological
   meaning, later rationalised as the acronym "Disk And Execution
   MONitor") A program that is not invoked explicitly, but lies
   dormant waiting for some condition(s) to occur.  The idea is
   that the perpetrator of the condition need not be aware that a
   daemon is lurking (though often a program will commit an
   action only because it knows that it will implicitly invoke a
   daemon).

   For example, under ITS writing a file on the LPT spooler's
   directory would invoke the spooling daemon, which would then
   print the file.  The advantage is that programs wanting files
   printed need neither compete for access to, nor understand any
   idiosyncrasies of, the LPT.  They simply enter their
   implicit requests and let the daemon decide what to do with
   them.  Daemons are usually spawned automatically by the
   system, and may either live forever or be regenerated at
   intervals.

   Unix systems run many daemons, chiefly to handle requests
   for services from other hosts on a network.  Most of these
   are now started as required by a single real daemon, inetd,
   rather than running continuously.  Examples are cron (local
   timed command execution), rshd (remote command execution),
   rlogind and telnetd (remote login), ftpd, nfsd (file
   transfer), lpd (printing).

   Daemon and demon are often used interchangeably, but seem to
   have distinct connotations (see demon).  The term "daemon"
   was introduced to computing by CTSS people (who pronounced
   it /dee'mon/) and used it to refer to what ITS called a
   dragon.

   [Jargon File]

   (1995-05-11)


Easton's 1897 Bible Dictionary:

Daemon
   the Greek form, rendered "devil" in the Authorized Version of
   the New Testament. Daemons are spoken of as spiritual beings
   (Matt. 8:16; 10:1; 12:43-45) at enmity with God, and as having a
   certain power over man (James 2:19; Rev. 16:14). They recognize
   our Lord as the Son of God (Matt. 8:20; Luke 4:41). They belong
   to the number of those angels that "kept not their first
   estate," "unclean spirits," "fallen angels," the angels of the
   devil (Matt. 25:41; Rev. 12:7-9). They are the "principalities
   and powers" against which we must "wrestle" (Eph. 6:12).