gyre

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." Gyre is also 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 tornadoes.