Eddy, Edge Wave, Emergent Coast, Equatorial Tide: Word Origins, Descriptions of Coastal Features, Processes

In the current alphabetic series of word origins and physical descriptions of coastal features and processes, here are eddy, edge wave, embayment, emergent coast, entrance, equatorial current, and equatorial tide.

Eddy
Modern English eddy comes from Middle English Scottish dialectal ydy, probably from Old Norse itha. The word is akin to many Indo-European forms with the basic meaning of "beyond," such as Old English ed- ("again"), Old High German and Old Norse ith- ("again"), Latin et ("and"), and Greek eti ("yet, still").

As a coastal phenomenon, an eddy is a current of water running contrary to the main current, especially in a circular manner. In some cases, an eddy develops into a whirlpool.

Edge Wave
An ocean wave that is parallel to the shoreline is an edge wave, that is, one that approaches the "edge" (border) of the beach in a basically parallel manner.

Embayment
In coastal terminology, the word embayment is commonly used in at least two different senses: the formation of a bay, as by the depression of the land near a river mouth so that the sea overflows it; and an indentation in a coastline forming a bay itself.

Emergent Coast
Modern English emergent comes from Middle English emergent, from Latin emergent-, a combining form of emergens, the present participle of emergere ("to emerge"), a combination of e- ("away") and mergere ("to plunge").

Emergent, in one of its general senses, means newly formed. An emergent coast is a coast where land formerly under water is now above sea level. This shift results from either a drop in the sea level or an uplift of the local land. Emergent coastlines are usually identifiable by the fact that their coastal landforms, such as raised beaches, are above the high-tide mark.

(A submergent coast shows the opposite characteristics. It has experienced a rise in sea level or a subsidence of local land.)

Entrance
On a coast, an entrance is an opening that separates the ocean from an inland body of water, such as a bay, a channel, or a mouth of a river.

Equatorial Current
On a coast, an equatorial current is a tidal current that occurs semimonthly when the moon is over the equator.

Equatorial Tide
A tide occurring semimonthly when the moon is over the equator is called an equatorial tide.
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Encyclopaedia Britannica Ready Reference 2004. CD-ROM. Encyclopaedia Britannica, 2004.

Merriam-Webster's Collegiate Dictionary. 11th ed. Springfield, Mass.: Merriam-Webster, 2006.

Merriam-Webster's Geographical Dictionary. 3rd ed. Springfield, Mass.: Merriam-Webster, 2007.

The Oxford English Dictionary. 2nd ed. Oxford, England: Clarendon Press, 1989.