The Collaborative International Dictionary of English v.0.48:

Deposition \Dep`o*si"tion\, n. [L. depositio, fr. deponere: cf.
   F. d['e]position. See Deposit.]
   1. The act of depositing or deposing; the act of laying down
      or thrown down; precipitation.
      [1913 Webster]

            The deposition of rough sand and rolled pebbles.
                                                  --H. Miller.
      [1913 Webster]

   2. The act of bringing before the mind; presentation.
      [1913 Webster]

            The influence of princes upon the dispositions of
            their courts needs not the deposition of their
            examples, since it hath the authority of a known
            principle.                            --W. Montagu.
      [1913 Webster]

   3. The act of setting aside a sovereign or a public officer;
      deprivation of authority and dignity; displacement;
      removal.
      [1913 Webster]

   Note: A deposition differs from an abdication, an abdication
         being voluntary, and a deposition compulsory.
         [1913 Webster]

   4. That which is deposited; matter laid or thrown down;
      sediment; alluvial matter; as, banks are sometimes
      depositions of alluvial matter.
      [1913 Webster]

   5. An opinion, example, or statement, laid down or asserted;
      a declaration.
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   6. (Law) The act of laying down one's testimony in writing;
      also, testimony laid or taken down in writing, under oath
      or affirmation, before some competent officer, and in
      reply to interrogatories and cross-interrogatories.

   Syn: Deposition, Affidavit.

   Usage: Affidavit is the wider term. It denotes any authorized
          ex parte written statement of a person, sworn to or
          affirmed before some competent magistrate. It is made
          without cross-examination, and requires no notice to
          an opposing party. It is generally signed by the party
          making it, and may be drawn up by himself or any other
          person. A deposition is the written testimony of a
          witness, taken down in due form of law, and sworn to
          or affirmed by the deponent. It must be taken before
          some authorized magistrate, and upon a prescribed or
          reasonable notice to the opposing party, that may
          attend and cross-examine. It is generally written down
          from the mouth of the witness by the magistrate, or
          some person for him, and in his presence.
          [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

147 Moby Thesaurus words for "deposition":
   admission, affidavit, affirmation, allegation, allocation,
   alluvion, alluvium, ash, assertion, asseveration, assignment,
   attest, attestation, authority, authorization, averment,
   avouchment, avowal, bill, bill of complaint, bill of health,
   cashiering, certificate, certificate of proficiency, certification,
   cinder, claim, clinker, collocation, complaint, compurgation,
   credential, declaration, deconsecration, defrocking, deployment,
   deposal, deposit, deposits, deprivation, dethronement, diluvium,
   diploma, disbarment, disbarring, disclosure, discrownment,
   disenthronement, dismissal, displacement, disposition, draff,
   dregs, dross, ember, emplacement, excommunication, expulsion,
   feces, firing, forced resignation, froth, grounds, impeachment,
   instrument in proof, kicking upstairs, lading, lees,
   legal evidence, libel, liquidation, loading, localization,
   locating, location, loess, manifesto, moraine, narratio, navicert,
   nolle prosequi, nonsuit, notarized statement, note, offscum,
   ousting, overthrow, overthrowal, packing, pensioning off,
   pinpointing, placement, placing, position paper, positioning,
   posting, precipitate, precipitation, profession, purge, putting,
   removal, reposition, retirement, scoria, scum, sediment, settlings,
   sheepskin, silt, sinter, situation, slag, smut, solemn declaration,
   soot, spotting, statement, statement of belief, statement of facts,
   statement under oath, stationing, storage, stowage, sublimate,
   superannuation, suspension, swearing, sworn evidence,
   sworn statement, sworn testimony, testamur, testimonial,
   testimonium, testimony, ticket, unchurching, unfrocking, unseating,
   visa, vise, voucher, vouching, warrant, warranty, witness, word