Word Origins of Arch, Arm, Attrition, Bank, Bar - Coastal Features, Processes

In the current alphabetic series of terms relating to coastal features and processes, here are arch, arm, attrition, bank, and bar.

Arch
Modern English arch comes from Middle English arche, from Middle French arche, from (assumed) Vulgar Latin arca, from Latin arcus ("bow, arch, arc").

An arch, in general, is a curved structure that spans the opening between two columns and supports a load from above.

A coastal arch, often called a natural arch, is an arch-shaped opening, created by the erosive action of waves, between two bodies of water through a headland.

Arm
Modern English arm comes from Middle English arm, from Old English earm. The word is akin to Latin armus ("shoulder") and Sanskrit irma ("arm").

From its original meaning of a human upper limb, the word arm has been extended to include anything suggesting an arm.

An inlet of water from a sea or an ocean is an arm of the larger body. The generic names given to such arms vary. For example, the Persian Gulf is an arm of the Arabian Sea, the Aegean Sea is an arm of the Mediterranean Sea, Puget Sound is an arm of the Pacific Ocean, and Hudson Strait is an arm of the Atlantic Ocean.

Attrition
The word attrition comes from Latin attrition-, a combining form of attritio, from atterere ("to rub against"), from ad- ("against") and terere ("to rub").

Attrition on a coast is the wearing down of rock particles while they are being moved about by waves and wind.

Bank
The topographical word bank goes back to the Middle English period and is probably of Scandinavian origin. It is related to Old Norse bakki ("bank") and Old English benc ("bench").

A bank, in general, is a mound or ridge. The rising ground bordering the water of a sea is a type of bank. The term bank also refers to a rising undersea elevation, especially a continental slope, the steep bank from a continental shelf to the ocean floor.

Bar
Modern English bar comes from Middle English barre, borrowed from Middle French barre.

A bar, in general, is a straight piece of something, usually longer than it is wide. A submerged or partly submerged bank, generally of sand, along a coast, is a bar. The term is often used specifically to denote such a bank that obstructs, or "bars," navigation.
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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.