dolphin

Etymology 1

From Middle English delphyn, from Latin delphīnus, from Ancient Greek δελφίς (delphís), from δελφύς (delphús, “womb”); the modern form in -ol- is probably influenced by the pronunciation of Middle French dauphin. Compare Swedish delfin. Doublet of dauphin. Displaced native Old English mereswīn (literally “sea pig”).

noun

1. A carnivorous aquatic mammal in one of several families of order Cetacea, famed for its intelligence and occasional willingness to approach humans.
   1. Tursiops truncatus, (Atlantic bottlenose dolphin) the most well-known species.
2. A fish, the mahi-mahi or dorado, Coryphaena hippurus, with a dorsal fin that runs the length of the body, also known for iridescent coloration.
3. (heraldry) A depiction of a fish, with a broad indented fin, usually embowed.
4. The dauphin, eldest son of the kings of France.
5. (history) A mass of iron or lead hung from the yardarm, in readiness to be dropped through the deck and the hull of an enemy's vessel to sink it.
6. (nautical) A kind of wreath or strap of plaited cordage.
7. (nautical) A spar or buoy held by an anchor and furnished with a ring to which ships may fasten their cables.
8. (nautical) A mooring post on a wharf or beach.
9. (nautical) A permanent fender designed to protect a heavy boat or coastal structure from the impact of large floating objects such as ice or floating logs.
   At each end of the piers in the water, in cases where several rows of pile are driven, a sort of cutwater should be formed, in order to ward off heavy bodies, such as floating trees, ice, etc. and prevent them from injuring the superstructure (called in German constructions, "Eisbrecher," or ice-breaker). This is usually done by driving one pile by itself in advance of the rest, or by forming what is called a "dolphin" at each end of the pier. 1844, The Technical Educator, an encyclopædia, page 107
   An ice-breaker or dolphin was also constructed during the latter part of the autumn, a little above the site for No. 2 dam, or that for the twoer nearest the Pesth shore; this dolphin, which served as a protection against the ice, rafts, &c. was constructed at this time, so that a means might be afforded of judging of the actual force of the ice during the winter ensuing; and the event proved that its construction was most fortunate, as the winter of 1840-41 was unusually severe. 1852, William Tierney Clark, An Account, with illustrations, of the Suspension Bridge across the River Danube, uniting Pesth with Buda and the adjacent country, in the Kingdom of Hungary, etc, page 37
   The Dolphin is now seldom used, but a rope treated in the same manner, with mousings raised on it at regular intervals, is sometimes put around a Launch, just below the gunwale outside and secured there as a sort of permanent fender; this also is called a Dolphin. 1868, Stephen Bleecker Luce, Seamanship, page 28
   For a dolphin or buoy to be placed on the south point of Goat Island, in the harbor of Newport, one hundred and fifty dollars. 1852, The Congressional Globe: Volume 32, page xxx
   Sometimes a stoppage would take place owing to the accumulation of ice between the Dolphin and the dam, which kept that above back until a mass of ice more resembling an island than anything else it can be compared to, would force the whole mass before it, breaking up the large blocks accumulated at the dam into a thousand pieces. March 31,1860, “Victoria Bridge”, in American Railroad Journal, volume 16, number 13
10. (military, obsolete) One of the handles above the trunnions by which a gun was lifted.

Etymology 2

Ultimately from 3rd Duke of Alba (duc-d’Albe in French), who was the first to build this type of structure in the Spanish Netherlands in the 16th century. Possibly from Dutch dukdalf, or the plural dukdalven, through elision of the initial duk-.

noun

1. (nautical) A man-made semi submerged maritime structure, usually installed to provide a fixed structure for temporary mooring, to prevent ships from drifting to shallow water or to serve as base for navigational aids.