這些術(shù)語均為普通法上的術(shù)語，有“抗辯”的含義。在普通法中，demurrer為訴辯狀呈送程序（pleadings)中就訴狀或反 訴中的指控提交的抗辯書，主要指被告方雖承認所控事實，但 卻以其法律依據(jù)不足以使訴訟成立為由而進行的抗辯[1]；其可分為普通抗辯 “general demurrer”，特殊抗辯 “special demurrer”和陳述性抗辯“speaking demurrer”三種。而confession and avoidance (也稱為 avoidance、plea in confession and avoidance 或 plea of confession and avoidance)則是承認所控事實，但卻提出新的附加事實以回避應(yīng)負的責任[2]。如同時提出混合過失 (contributory negligence)以回避自己應(yīng)當負的部分責任的抗辯則可稱為是confession and avoidance。相比之下，plea則主要對所控事實或訴因進行反駁而作的抗辯；尤指在民事訴訟中被告呈送的首次 pleading 。exception 作抗辯時，常指 exceptions for insufficiency of a pleading,表示—種以訴狀要件不完善或有缺陷為由的抗辯。根據(jù)現(xiàn)行《美國聯(lián)邦訴訟法典》的規(guī)定，demurrers, pleas 和 exceptions for insufficiency of a pleading 均已被廢除， 代之以起的是motion和answer;但在有些州，上述抗辯仍在適用。
    
[1]“ A pleading stating that although the facts alleged in a complaint may be true，they
are insufficient for the plaintiff to state a claim for relief and for the defendant to frame an answer. ”Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 448, West Group (1999).
[2]“ A common-law plea in which a party confesses an allegation but alleges additional facts to avoid the intended legal effect of the original allegation. ”Cf. Linda Picard Wood, J. D.，Merriam Webster's Dictionary of Law，at p. 95, Merriam-Webster, Incorporated (1996).
[3]“ In common law a pleading; any one in the series of pleadings. More particularly，the first pleading on defendant. ”Cf. The Publisher's Editorial Staff, Black's Law Dictionary, abridged 6th edition, at p. 797，West Publishing Co. (1991).