gyration

noun

Etymology: From gyre (“to spin around; to gyrate, to whirl; (rare) to make (something) spin or whirl around; to spin, to whirl”) + -ation (suffix indicating actions or processes). Gyre is from Late Middle English giren (“to turn (something) away; to cause (something) to revolve or rotate; to travel in a circle”), from Old French girer (“to turn”), and directly from its etymon Latin gȳrāre, the present active infinitive of gȳrō (“to turn in a circle, rotate; to circle or revolve around”) (from gȳrus (“circle; circular motion; circuit, course”), from Ancient Greek γῦρος (gûros, “a circle, a ring”), from Proto-Indo-European *gew- (“to bend; to curve”)) + -ō (suffix forming regular first-conjugation verbs).

1. The act of turning or whirling, especially around a fixed axis or centre; a circular or spiral motion; rotation.

   “Novv that the ayre impelled returnes unto its place in a gyration or vvhirling, is evident from the Atomes or moates in the Sun. For vvhen the Sunne ſo enters a hole or vvindovv, that by its illumination the Atomes or moates become perceptible, if then by our breath the ayre bee gently impelled, it may be perceived that they vvill circularly returne, and in a gyration unto their places againe.”

   “If Regularity and ſteddineſs accompany Velocity; the motion then leaves not the leaſt track in the ſenſitive. Thus a French Top, the common recreation of School-boys, throvvn from a cord vvhich vvas vvound about it, will ſtand as if it vvere fixt on the floor it lighted; and yet continue in its repeated Gyrations, vvhile the ſenſe diſcovers not the leaſt footſteps of that præcipitate Rotation.”

2. The act of turning or whirling, especially around a fixed axis or centre; a circular or spiral motion; rotation.
3. One of the whorls of a spiral univalve shell.
4. The arrangement of convolutions of gyri in the cerebral cortex of the brain.