Gyre

   A gyre is a circular or spiral motion or form; especially : a giant circular oceanic surface feature made up of currents and winds that spiral around a central point and push water and marine debris to its centre.

The word is also used metaphorically as in the following sentence ffom 'The Professor and the Madman' by Simon Winchester  -  "A hundred years ago it was positively vile.  It was still then low,marshy, and undrained, a swampy gyre of pathways where one sad little stream called the Neckinger seeped into the Thames."