The Collaborative International Dictionary of English v.0.48:

Amanuensis \A*man`u*en"sis\, n.; pl. Amanuenses. [L., fr. a,
   ab + manus hand.]
   A person whose employment is to write what another dictates,
   or to copy what another has written.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amanuensis
    n 1: someone skilled in the transcription of speech (especially
         dictation) [syn: stenographer, amanuensis, shorthand
         typist]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "amanuensis":
   Federal, accountant, agent, archivist, baggage agent, bookkeeper,
   business agent, calligrapher, chirographer, claim agent, clerk,
   commercial agent, commission agent, consignee, copier, copyist,
   customer agent, documentalist, dupe, engraver, factor, fed,
   federal agent, filing clerk, freight agent, functionary,
   general agent, implement, ink spiller, inkslinger, instrument,
   insurance agent, land agent, law agent, letterer, librarian,
   literary agent, loan agent, marker, news agent, notary,
   notary public, official, parliamentary agent, passenger agent, pen,
   pencil driver, penman, penner, press agent, prothonotary, puppet,
   purchasing agent, real estate agent, record clerk, recorder,
   recording secretary, recordist, register, registrar, sales agent,
   scorekeeper, scorer, scribbler, scribe, scrivener, secretary,
   special agent, station agent, stenographer, steward, stonecutter,
   theatrical agent, ticket agent, timekeeper, tool, transcriber,
   travel agent, walking delegate, word-slinger, writer



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

AMANUENSIS. One who write another dictates. About the beginning of the sixth
century,, the tabellions (q.v.) were known by this name. 1 Sav. Dr. Rom.
Moy. Age, n. 16.