The Collaborative International Dictionary of English v.0.48:

Reply \Re*ply"\, n.; pl. Replies (-pl?z"). [See Reply, v.
   i., and cf. Replica.]
   That which is said, written, or done in answer to what is
   said, written, or done by another; an answer; a response.
   [1913 Webster]

   Syn: Answer; rejoinder; response.

   Usage: Reply, Rejoinder, Answer. A reply is a distinct
          response to a formal question or attack in speech or
          writing. A rejoinder is a second reply (a reply to a
          reply) in a protracted discussion or controversy. The
          word answer is used in two senses, namely (1), in the
          most general sense of a mere response; as, the answer
          to a question; or (2), in the sense of a decisive and
          satisfactory confutation of an adversary's argument,
          as when we speak of a triumphant answer to the speech
          or accusations of an opponent. Here the noun
          corresponds to a frequent use of the verb, as when we
          say. "This will answer (i.e., fully meet) the end in
          view;" "It answers the purpose."
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Reply \Re*ply"\ (r?-pl?"), v. i. [imp. & p. p. Replied
   (-pl?d"); p. pr. & vb. n. Replying.] [OE. replien, OF.
   replier, F. r['e]pliquer, fr. L. replicare to fold back, make
   a reply; pref. re- re- + plicare to fold. See Ply, and cf.
   Replica.]
   1. To make a return in words or writing; to respond; to
      answer.
      [1913 Webster]

            O man, who art thou that repliest against God?
                                                  --Rom. ix. 20.
      [1913 Webster]

   2. (Law) To answer a defendant's plea.
      [1913 Webster]

   3. Figuratively, to do something in return for something
      done; as, to reply to a signal; to reply to the fire of a
      battery.
      [1913 Webster]

   Syn: To answer; respond; rejoin.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Reply \Re*ply"\, v. t.
   To return for an answer. --Milton.
   [1913 Webster]

         Lords, vouchsafe
         To give me hearing what I shall reply.   --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reply
    n 1: a statement (either spoken or written) that is made to
         reply to a question or request or criticism or accusation;
         "I waited several days for his answer"; "he wrote replies
         to several of his critics" [syn: answer, reply,
         response]
    2: the speech act of continuing a conversational exchange; "he
       growled his reply" [syn: reply, response]
    v 1: react verbally; "She didn't want to answer"; "answer the
         question"; "We answered that we would accept the
         invitation" [syn: answer, reply, respond]

Moby Thesaurus II by Grady Ward, 1.0:

172 Moby Thesaurus words for "reply":
   ESP, acknowledge, acknowledgment, action and reaction, advocate,
   allege in support, answer, answer back, answering, antiphon,
   approach, argue for, argument, assert, automatic reaction,
   autonomic reaction, back answer, back talk, backchat, billet,
   boomerang, bounceback, business letter, champion, chit, come back,
   come back at, come in, comeback, commerce, communicate with,
   communication, communion, congress, connection, contact,
   contend for, conversation, converse, correspond, correspondence,
   counter, counterblast, counterblow, counterstatement,
   counterstroke, dealing, dealings, defend, defense, demurrer,
   denial, dispatch, echo, epistle, espouse, establish connection,
   evasive reply, exception, exchange, favor, flash back, get to,
   give acknowledgment, give answer, give-and-take, information,
   interaction, interchange, intercommunication, intercommunion,
   intercourse, interplay, interrogate, letter, line,
   linguistic intercourse, maintain, maintain connection, make a plea,
   make advances, make contact with, make overtures, make up to,
   message, missive, note, objection, plea, plead for, pleading,
   predictable response, question, raise, reach, react, reaction,
   ready reply, rebut, rebuttal, receipt, reciprocation, recoil,
   reecho, reflection, reflex, reflex action, refluence, reflux,
   refutation, refute, rejoin, rejoinder, relate to, repartee,
   replication, reply to, repost, rescript, rescription, respond,
   respond to, respondence, response, responsion, responsory,
   retaliation, retort, retroaction, return, return answer,
   return for answer, reverberate, reverberation, revulsion, riposte,
   rise, say, say in defense, say in reply, shoot back, short answer,
   snap back, snappy comeback, social intercourse, speak for,
   speak up for, speaking, special demurrer, special pleading, speech,
   speech circuit, speech situation, stand up for,
   statement of defense, stick up for, support, sustain,
   take the bait, talk back, talking, telepathy, touch, traffic,
   truck, two-way communication, unthinking response, uphold,
   urge reasons for, witty reply, witty retort, yes-and-no answer



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

reply
 n.

    See followup.


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

followup
reply

   On Usenet, a posting generated in response to another
   posting (as opposed to a reply, which goes by e-mail rather
   than being broadcast).  Followups include the ID of the
   parent message in their headers; smart news-readers can use
   this information to present Usenet news in "conversation"
   sequence rather than order-of-arrival.  See thread.

   [Jargon File]