What is Appeal?

Legal Definition
A challenge to a previous legal determination. An appeal is directed towards a legal power higher than the power making the challenged determination. In most states and the federal system, trial court determinations can be appealed in appeals courts, and appeals court decisions can be appealed in a supreme court. The person pursuing an appeal is called an appellant, while the person defending the lower court’s ruling is the appellee.
Legal Definition
English crim. law. The accusation of a person, in a legal form, for a crime committed by him; or, it is the lawful declaration of another man's crime, before a competent judge, by one who sets his name to the declaration, and undertakes to prove it, upon the penalty which may ensue thereon. Vide Co. Litt. 123 b, 287 b; 6 Burr. R. 2643, 2793; 2 W. Bl. R. 713; 1 B. & A. 405. Appeals of murder, as well as of treason, felony, or other offences, together with wager of battle, are abolished by stat. 59 Geo. M. c. 46.
-- Bouviers Law Dictionary
Legal Definition
Practice. The act by which a party submits to the decision of a superior court, a cause which has been tried in an inferior tribunal. 1 S. & R. 78 Bin. 219; 3 Bin. 48.

2. The appeal generally annuls the judgment of the inferior court, so far that no action can be taken upon it until after the final decision of the cause. Its object is to review the whole case, and to secure a just judgment upon the merits.

3. An appeal differs from proceedings in error, under which the errors committed in the proceedings are examined, and if any have been committed the first judgment is reversed; because in the appeal the whole case is exainined and tried as if it had not been tried before. Vide Dane's Ab. h. t.; Serg. Const. Law Index, h. t. and article Courts of the United States.
-- Bouviers Law Dictionary
Legal Definition
In civil practice. The complaint to a superior court of an injustice done or error committed by an inferior one, whose judgment or decision the court abave is called upon to correct or reverse. The removal of a cause from a court of. inferior to one of superior jurisdiction, for the purpose of obtaining a review and retrial. Wiscart v. Dauchy, 3 Dali. 321, 1 In Ed. 619. The distinction between an appeal and a writ of error is that an appeal is a process of civil law origin, and removes a cause entirely, subjecting the facte, as well as the law, to a review and reyisal; but a writ of error is of common law origin, and it removes nothing for re-er-amination but the law. Wiscart v. Dauchy, 3 Dali. 321, 1 In Ed. 619; In S. v. Goodwin, 7 Cranch, 108, 3 L. Ed. 284; Cunningham V. Neagle, 135 U. S. 1, 10 Sup. Ct. 658, 34 L. Ed. 55. But appeal is sometimes used to denote the nature of appellate jurisdiction, as distinguished from original jurisdiction, without any particular regard to the mode by which a cause la transmitted to a superior jurisdiction. U. S. v. Wonson. 1 Gall. 5, 12, Fed. Cas. No. 16,750. In criminal practice. A formal accusation made by one private person against another of having committed some heinous crime, 4 Bl. Comm. 312. Appeal was also the name given to the proceeding in English law where a person, indicted of treason or felony, and arraigned for the same, confessed the fact before plea pleaded, and appealed, or acoused others, his accomplicos in the same crime, in order to obtain his pardon. In this case he was called an "approver" or "prover," and the party appealed or accused, the "appellee." 4 BL Comm. 330. In legislation. The act by which a mem-bar of a legislative body who questions the correctness of a decision of the presiding officer, or "chair," prochres a vote of the body upon the decision. In old French law. A mode of proceeding in the lords' courts, where a party was dissatisfied with the judgment of the peers, which was by accusing them of having given a false or malicious judgment, and offering to make good the charge by the duel or combat. This was called the "appeal of false Judgment." Montesq. Esprit des Lois, llv. 28, c. 27.
See also
-- Black's Law Dictionary
Legal Definition
The transfer of a cause to a higher court for review or for a new trial, used also to denote “Appeal of felony.”
-- Ballentine's Law Dictionary