What is Sea Shore?

Legal Definition
Property. That space of land, on the border of the sea, which is alternately covered and left dry, by the rising and falling of the tide or, in other words, that space of land between high and low water mark. Hargr, Tr. 12; 6 Mass. 435, 439; 1 Pick. 180, 182; 5 Day, 22.

2. Generally, the sea shore belongs to the public. Angell on Tide Wat. 34, 5; 3 Kent's Com. 347.

3. By the Roman law, the shore included the land as far as the greatest wave extended in winter; est autem littus, maris, quatenus hibernus, fluctus maximus excurrit. Inst. lib. 2, t. 1, s. 3. Littus publicum est eatenus qua maxime fluctus exaestuat. Dig., lib, 50, t. 16, s. 112.

4. The Civil Code of Louisiana seems to have followed the law of the Insti-tutes and the Digest, for it enacts, art. 442, that the "sea shore is that space, of land over which the waters of the sea are spread in the highest water, during the winter season." Vide. 5 Rob. Adm. R. 182; Dougl. 425; 1 Halst. R. 1; 2 Roll. Ab. 170; Dyer, 326; 5 Co. 107; Bac. Ab., Courts of Admiralty,, A; 1 Am. Law Mag. 76; 16 Pet. R. 234, 367 Ang. on Tide Waters, Index, tit. Shore; 2 Bligh's N, S. 146; 5 M. & W. 327 Merl. Quest. de Droit, mots Rivage de la Mer; Inst. 2, 1, 2; 22 Maine, R. 350. For the law of Mass. vide Dane's Ab. c. 68, a 3, 4.
-- Bouviers Law Dictionary
Legal Definition
The margin of the sea in its usual and ordinary state. When the tide is out, low-water mark is the margin of the sea ; and, When the sea is full, the margin is high-water mark. The sea-shore is therefore all the ground between the ordinary high-water mark and low-water mark. It cannot be considered as including any ground always covered by the sea, for then it would have no definite limit on the sea-board. Neither can it include any part of the upland, for the same reason. Storer v. Freeman, 6 Mass. 439, 4 Am. Dec. 155 ; Church v. Meeker, 34 Conn. 424. That space of land over which the waters of the sea are spread in the highest water during the winter season. Civ. Code La. art. 442.
-- Black's Law Dictionary