Meaning

noun a single complete turn (axial or orbital)

noun the act of rotating in a circle or spiral

originFrom 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…

Etymology from Wiktionary, CC BY-SA 3.0