Definitions from Black's Law Dictionary: 2nd Edition and Ballentine's Law Dictionary as are available for each term in each dictionary.
  • Black's Law Dictionary: 2nd Edition

    In Its use in Jurisprudence, this word is the correlative of right. Thus, wherever there exists a right in any person, there also rests a corresponding duty upon some other person or upon all persons generally. But it is also used, in a wider sense, to designate that class of moral obligations which lie outside the jural sphere; such, namely, as rest upon an imperative ethical basis, but have not been recognized by the law as within its proper province for purposes of enforcement or redress. Thus, gratitude towards a benefactor is a duty, but its refusal will not ground an action. In this meaning "duty" is the equivalent of "indral obligation." as distinguished from a "legal obligation." See Kentucky v. Dennison, 24 How. 107, 16 Lu Ed. 717; Harrison T. Bush, 5 El. & Bl. 349. As a technical term of the law, "duty" signifies a thing due; that which is due from a person; that which a person owes to another. An obligation to do a thing. A word of more extensive signification than "debt," although both are expressed by the same Latin word "debitum." Beach v. Boynton, 26 Vt 725, 733. But in practice it is commonly reserved as the designation of those obligations of performance, care, or observance which rest upon a person in an official or fiduciary capacity ; as the duty of an executor, trustee, manager, etc. It also denotes a tax or Impost due to the government upon the importation or exportation of goods.
    —Legal duty. An obligation arising from contract of the parties or the operation of the law. Riddell v. Ventilating Co., 27 Mont. 44, 69 Pac. 241. That which the law requires to be done or forborne to a determinate person or the public at large, correlative to a vested and coextensive right in such person or the public, and the breach of which constitutes negligence. Heaven v. Pender, 11 Q. B. Div. 506; Smith v. Clarke Hardware Co., 100 Ga. 163, 28 S. E. 73, 39 L. R. A. 607: Railroad Co. v. Ballentine, 84 Fed. 935, 28 C. C. A. 572.