The Collaborative International Dictionary of English v.0.48:

Concatenate \Con*cat"e*nate\ (k[o^]n*k[a^]t"[-e]*n[=a]t), v. t.
   [imp. & p. p. Concatenated; p. pr. & vb. n.
   Concatenating.] [L. concatenatus, p. p. of concatenare to
   concatenate. See Catenate.]
   To link together; to unite in a series or chain, as things
   depending on one another.
   [1913 Webster]

         This all things friendly will concatenate. --Dr. H.
                                                  More
   [1913 Webster]

WordNet (r) 3.0 (2006):

concatenate
    v 1: combine two strings to form a single one
    2: add by linking or joining so as to form a chain or series;
       "concatenate terms"; "concatenate characters"

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "concatenate":
   accouple, accumulate, agglutinate, amass, articulate, assemble,
   associate, band, be continuous, bond, bracket, bridge, bridge over,
   catenate, cement, chain, clap together, collect, combine, comprise,
   conglobulate, conjoin, conjugate, connect, connect up, continuate,
   continue, copulate, couple, cover, embrace, encompass,
   form a series, gather, glue, include, join, knot, lay together,
   league, link, lump together, maintain continuity, marry, marshal,
   mass, merge, mobilize, pair, piece together, put together,
   roll into one, run on, solder, span, splice, stick together,
   string, string together, take in, tape, thread, tie, unify, unite,
   weld, yoke



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

concatenate

    To join together two or more files or lists to form
   one big one.

   The Unix cat command can be used to concatenate files.

   (1995-12-22)