Word of the Week 12/22/19: Gyre

From Merriam-Webster:

(noun) : a circular or spiral motion or form
especially : a giant circular oceanic surface current
(verb) to move in a circle or spiral

William Butler Yeats opens his 1920 poem, "The Second Coming," with the following lines: "Turning and turning in the widening gyre / The falcon cannot hear the falconer; / Things fall apart; the center cannot hold; / Mere anarchy is loosed upon the world…." Often found in poetic or literary contexts as an alternative to the more familiar "circle" or "spiral," "gyre" comes via the Latin gyrus from the Greek gyros, meaning "ring" or "circle." Today, "gyre" is most frequently encountered as an oceanographic term that refers to vast circular systems of ocean currents, such as the North Atlantic Gyre, a system of currents circling clockwise between Europe, Africa, and the Americas. "Gyre" is also sometimes used of more localized vortices such as those produced by whirlpools or tornados.

From Wikipedia:

In oceanography, a gyre is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect; planetary vorticity along with horizontal and vertical friction, determine the circulation patterns from the wind stress curl (torque).

From NOAA.gov:

There are five major gyres, which are large systems of rotating ocean currents. The ocean churns up various types of currents. Together, these larger and more permanent currents make up the systems of currents known as gyres.

Wind, tides, and differences in temperature and salinity drive ocean currents. The ocean churns up different types of currents, such as eddies, whirlpools, or deep ocean currents. Larger, sustained currents—the Gulf Stream, for example—go by proper names. Taken together, these larger and more permanent currents make up the systems of currents known as gyres.

There are five major gyres: the North and South Pacific Subtropical Gyres, the North and South Atlantic Subtropical Gyres, and the Indian Ocean Subtropical Gyre.

In some instances, the term “gyre” is used to refer to the collections of plastic waste and other debris found in higher concentrations in certain parts of the ocean. While this use of "gyre" is increasingly common, the term traditionally refers simply to large, rotating ocean currents.

ed. note: pronounced with a soft 'g', rhymes with 'wire'