两者的区别在于law merchant为“商业法则”（此时的merchant 不是名词而是形容词 ） ， 指的是按中世纪英国普通法所发展而成的商事规则，包括有关调整商人关系的习惯和规则、商事方面的惯例、规章、原则等，其对现代的commercial law有较大影响，在美国《统一商法典》和各州法典中，其被当作补充性规则（supplementing rules)[1]。commercial law 则为“商法”， 所指范围极广，包括与商业有关的各种法律，如合同、代理、 买卖、流通票证、产权文据、破产等[2]。但在美国，commercial law所扩展的领域并未为人们认可，故在美国，其与law merchant 的区别没有在其他欧洲国家那样大，它们经常被人当作同义词相互替换使用[4]。

[1]“ The commercial rules developed under English common law that influenced modern commercial law and that are referred to as supplementing rules set down in the Uniform Commercial Code and in state codes. ”Cf. Linda Picani Wood, J. D. , Merriam Webster's Dictionary of Law, at p. 282，Memam-Webster, Incorporated (1996).

[2]“A phrase used to designate the whole body of substantive jurisprudence applicable to the rights, intercourse, and relations of persons engaged in commerce，trade, or mercantile pursuit. ”Cf. The Publisher's Editorial Staff，Black's Law Dictionary, abridged 6th edition, at p. 185, West Publishing Co. (1991 ).

[3]“Today the term commercial law has assumed a new meaning, a meaning that is new at least to Europe, but not so to the United States or to Louisiana. I refer, of course，to the meaning in which the term is used to describe a certain area of expertise in legal practice or learning, or that branch of law... of special interest to business people. ” Cf. Max Rheinstein，Problems and Obligations, in Essays on the Civil Law of Obligations, at pp. 10—11， Joseph Dainow ed. (1969).

[4] Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 893，West Group (1999).