sea-slug eaten as a delicacy in the Western Pacific, 1814, from French bêche-de-mer, literally "spade of the sea," a folk-etymology alteration of Portuguese bicho do mar "sea-slug," literally "worm of the sea."

also sea-shore, "coast of the sea, land that lies adjacent to the ocean," 1520s, from sea + shore (n.). Old English used særima "sea-rim," sæ-strande, etc. Middle English had sea-bank (mid-14c.); see seaside. Commonly understood as the ground between the ordinary high-water and low-water marks, typically covered with sand or shingle.

1805, "a promenade by the sea," from Spanish or Italian marina "shore, coast," from Latin marinus "of the sea, maritime," from mare "sea, the sea, seawater," from PIE root *mori- "body of water." Meaning "dock or basin with moorings for yachts and small craft" is 1935, American English.

before vowels thalass-, word-forming element meaning "sea, the sea," from Greek thalassa "the sea" (in Homer, when used of a particular sea, "the Mediterranean," as opposed to ōkeanos), a word from the Pre-Greek substrate language. In Attic Greek thalatta, hence sometimes thalatto-.

"a harbor on the sea; a city or town on such a harbor," 1590s, from sea + port (n.1).

"a pickle for fish or meat, generally of wine and vinegar with herbs and spices," 1704, from French marinade "spiced vinegar or brine for pickling," from mariner "to pickle in (sea) brine," from Old French marin (adj.) "of the sea," from Latin marinus "of the sea," from mare "sea, the sea, seawater," from PIE root *mori- "body of water." As a verb, "to steep in a marinade," from 1680s. Related: Marinaded; marinading.

by 1766, "well-adapted for voyaging, in fit condition to encounter heavy weather at sea," from sea + worthy. Related: Seaworthiness. Old English had særof "hardy at sea."

also haaf, Baltic lagoon, separated from open sea by a sandbar, German, from Middle Low German haf "sea," from Proto-Germanic *hafan (source also of Old Norse haf, Swedish haf "the sea," especially "the high sea," Danish hav, Old Frisian hef, Old English hæf "sea"), perhaps literally "the rising one," and related to the root of heave, or a substratum word from the pre-Indo-European inhabitants of the coastal regions. The same word as haaf "the deep sea," which survived in the fishing communities of the Shetland and Orkney islands.

also sea-sick, "affected with nausea from the motion of a vessel," 1560s, from sea + sick (n.). Related: Seasickness. Middle English se-sik meant "weary of travelling on the sea" (mid-15c.).

also sea-side, "the land bordering on the sea, the margin or brim of the sea," c. 1200, from sea + side (n.). Especially in England, "the seacoast as a resort for pleasure or health," 1782; as an adjective in this sense from 1781. The meaning "the side facing the sea" seems to be late (19c.) and rare.

Other Middle English "seaside, seashore" words included sees koste (mid-14c.), sewarth (Old English sæwaroþ, from wār "seashore, beach"), se-ground, se-brimme, sæ-strand, sea-half (Old English sæhealf), se-bank (mid-14c.). Old English used særima "sea-rim," sæ-strande, etc.