respondent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One who responds.
• noun Law The defending party in certain legal proceedings, as in a case brought by petition.
• adjective Giving or given as an answer; responsive.
• adjective Law Of or being a respondent in a proceeding.

from The Century Dictionary.

• noun A defendant in a lawsuit, now specifically in a divorce case.
• Answering; responding.
• Conformable; corresponding.
• noun One who responds; specifically, in a scholastic disputation, one who maintains a thesis, and defends it against the objections of one or more opponents.
• noun Specifically One who answers or is called on to answer a petition or an appeal.
• noun In mathematics, a quantity in the body of a table: opposed to argument, or the regularly varying quantity with which the table is entered.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Disposed or expected to respond; answering; according; corresponding.
• noun (Law) One who answers in certain suits or proceedings, generally those which are not according to the course of the common law, as in equity and admiralty causes, in petitions for partition, and the like; -- distinquished from appellant.
• noun One who maintains a thesis in reply, and whose province it is to refute objections, or overthrow arguments; -- distinguished from opponent.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law person who answers for the defendant in a case before a court. In some legal systems, when one appeals a criminal case, one names the original court as defendant, but the state is the respondent.
• noun One who responds. See also correspondent.
• noun Person that participates in research involving questionnaires.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective replying
• noun someone who responds
• noun the codefendant (especially in a divorce proceeding) who is accused of adultery with the corespondent