What is Derelict?

Legal Definition
Common law. This term is applied in the common law in a different sense from what it bears in the civil law. In the former it is applied to lands left by the sea.

2. When so left by degrees the derelict land belongs to the owner of the soil adjoining but when the sea retires suddenly, it belongs to the government. 2 Bl. Com. 262 1 Bro. Civ. Law, 239; 1 Sumn. 328, 490 1 Gallis. 138; Bee, R. 62, 178, 260; Ware, R. 332.
-- Bouviers Law Dictionary
Legal Definition
Forsaken; abandoned; deserted ; cast away. Personal property abandoned or thrown away by the owner in such manner as to indicate that he intends to make no further claim thereto. 2 Bl. Comm. 9; 2 Reeve, Eng. Law, 9. Land left uncovered by the receding of water from its former bed. 2 Rolle, Abr. 170; 2 Bl. Comm. 262; 1 Crabb, Real Prop. 109. In maritime law. A boat or vessel found entirely deserted or abandoned on the sea, without hope or Intention of recovery or return by the master or crew, whether resulting from wreck, accident, necessity, or voluntary abandonment. U. S. v. Stone (0. C.) 8 Fed. 243; Cromwell v. The Island City, 1 Black, 121, 17 In Ed. 70; The Hyderabad (D. C.) 11 Fed. 754; The Fairfield (D. C.) 30 Fed. 700; The Aquila, 1 C. Rob. 41. See Quasi derelict.
-- Black's Law Dictionary
Legal Definition
Abandoned.
-- Ballentine's Law Dictionary