The Collaborative International Dictionary of English v.0.48:

Sequel \Se"quel\ (s[=e]"kw[e^]l), n. [L. sequela, fr. sequit to
   follow: cf. F. s['e]quelle a following. See Sue to follow.]
   1. That which follows; a succeeding part; continuation; as,
      the sequel of a man's advantures or history.
      [1913 Webster]

            O, let me say no more!
            Gather the sequel by that went before. --Shak.
      [1913 Webster]

   2. Consequence; event; effect; result; as, let the sun cease,
      fail, or swerve, and the sequel would be ruin.
      [1913 Webster]

   3. Conclusion; inference. [R.] --Whitgift.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sequel
    n 1: something that follows something else [syn: sequel,
         subsequence]
    2: a part added to a book or play that continues and extends it
       [syn: sequel, continuation]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "sequel":
   aftereffect, aftermath, alternation, by-product, chain, chasing,
   close, closing, conclusion, consecution, consequence, consequent,
   continuation, corollary, derivation, derivative, descendant,
   development, distillate, dogging, dynasty, effect, end, ending,
   event, eventuality, eventuation, finish, finishing, follow-up,
   following, fruit, harvest, heeling, heir, hounding, issue, legacy,
   line, lineage, logical outcome, offshoot, offspring, order,
   outcome, outgrowth, posterity, precipitate, product, progression,
   pursual, pursuance, pursuit, result, resultant, row, sequela,
   sequence, sequent, series, shadowing, successor, supplement,
   tailing, termination, trailing, train, upshot



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

SEQUEL
       Structured English QUEry Language (IBM, DB, SQL, predecessor)


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

Sequel

   1. Precursor to SQL.

   ["System R: Relational Approach to Database Management", IBM
   Res Lab, San Jose, reprinted in Readings in Database Systems].

   2. U Leeds.  Theorem prover specification language.  Pattern
   matching notation similar to Prolog.  Compiled into Lisp.

   [Proc ICJAI 13].

   (ftp://agora.leeds.ac.uk/scs/logic/).