The Collaborative International Dictionary of English v.0.48:

Interpreter \In*ter"pret*er\, n. [Cf. OF. entrepreteur, L.
   interpretator.]
   One who or that which interprets, explains, or expounds; a
   translator; especially, a person who translates orally
   between two parties.
   [1913 Webster]

         We think most men's actions to be the interpreters of
         their thoughts.                          --Locke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

interpreter
    n 1: someone who mediates between speakers of different
         languages [syn: interpreter, translator]
    2: someone who uses art to represent something; "his paintings
       reveal a sensitive interpreter of nature"; "she was famous as
       an interpreter of Shakespearean roles"
    3: an advocate who represents someone else's policy or purpose;
       "the meeting was attended by spokespersons for all the major
       organs of government" [syn: spokesperson, interpreter,
       representative, voice]
    4: (computer science) a program that translates and executes
       source language statements one line at a time [syn:
       interpreter, interpretive program]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "interpreter":
   allegorist, annotator, artist, artiste, cicerone, clarifier,
   commentator, concert artist, critic, cryptanalyst, cryptographer,
   cryptologist, decoder, definer, demonstrator, demythologizer,
   diaskeuast, dragoman, editor, emendator, emender, euhemerist,
   executant, exegesist, exegete, exegetist, explainer, explicator,
   exponent, expositor, expounder, go-between, guide, hermeneut,
   lexicographer, maestro, metaphrast, minstrel, minstrelsy,
   music maker, musician, oneirocritic, paraphrast, performer, player,
   scholiast, soloist, textual critic, translator, tunester, virtuosa,
   virtuoso



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

interpreter
interpreted

    A program which executes other programs.  This
   is in contrast to a compiler which does not execute its
   input program (the "source code") but translates it into
   executable "machine code" (also called "object code")
   which is output to a file for later execution.  It may be
   possible to execute the same source code either directly by an
   interpreter or by compiling it and then executing the machine
   code produced.

   It takes longer to run a program under an interpreter than to
   run the compiled code but it can take less time to interpret
   it than the total required to compile and run it.  This is
   especially important when prototyping and testing code when an
   edit-interpret-debug cycle can often be much shorter than an
   edit-compile-run-debug cycle.

   Interpreting code is slower than running the compiled code
   because the interpreter must analyse each statement in the
   program each time it is executed and then perform the desired
   action whereas the compiled code just performs the action.
   This run-time analysis is known as "interpretive overhead".
   Access to variables is also slower in an interpreter because
   the mapping of identifiers to storage locations must be done
   repeatedly at run time rather than at compile time.

   There are various compromises between the development speed
   when using an interpreter and the execution speed when using a
   compiler.  Some systems (e.g. some Lisps) allow interpreted
   and compiled code to call each other and to share variables.
   This means that once a routine has been tested and debugged
   under the interpreter it can be compiled and thus benefit from
   faster execution while other routines are being developed.
   Many interpreters do not execute the source code as it stands
   but convert it into some more compact internal form.  For
   example, some BASIC interpreters replace keywords with
   single byte tokens which can be used to index into a jump
   table.  An interpreter might well use the same lexical
   analyser and parser as the compiler and then interpret the
   resulting abstract syntax tree.

   There is thus a spectrum of possibilities between interpreting
   and compiling, depending on the amount of analysis performed
   before the program is executed.  For example Emacs Lisp is
   compiled to "byte-code" which is a highly compressed and
   optimised representation of the Lisp source but is not machine
   code (and therefore not tied to any particular hardware).
   This "compiled" code is then executed (interpreted) by a byte
   code interpreter (itself written in C).  The compiled code
   in this case is machine code for a virtual machine which
   is implemented not in hardware but in the byte-code
   interpreter.

   See also partial evaluation.

   (1995-01-30)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

INTERPRETER. One employed to make a translation. (q v.)
     2. An interpreter should be sworn before he translates the testimony of
a witness. 4 Mass. 81; 5 Mass. 219; 2 Caines' Rep. 155.
     3. A person employed between an attorney and client to act as
interpreter, is considered merely as the organ between them, and is not
bound to testify as to what be has acquired in those confidential
communications. 1 Pet. C. C. R.. 356; 4 Munf. R. 273; 1 Wend. R. 337. Vide
Confidential Communications.



The Devil's Dictionary (1881-1906):

INTERPRETER, n.  One who enables two persons of different languages to
understand each other by repeating to each what it would have been to
the interpreter's advantage for the other to have said.