The word "gyre" means a swirling or circular motion, like a whirlpool or a spinning vortex. It describes something that is turning or rotating in a circular manner. Full definition
This subtropical gyre of warm North Atlantic Central Water is the hub of the energy that drives the North Atlantic circulation. (britannica.com)
Such accumulation zones are created when large amounts of floating plastic debris are caught by ocean currents and concentrate in the centre of gyre systems. (sciencedaily.com)
To figure out how much refuse is floating in those garbage patches, four ships of the Malaspina expedition, a global research project studying the oceans, fished for plastic across all five major ocean gyres in 2010 and 2011. (sciencemag.org)