Is it ensure, insure, or assure?
fuck the dog (1950s+ Nautical)
rotary oceanic current, a large-scale eddy that is produced by the interaction of rising and falling tides. Similar currents that exhibit a central downdraft are termed vortexes and occur where coastal and bottom configurations provide narrow passages of considerable depth. Slightly different is vortex motion in streams; at certain stages of turbulent flow, rotating currents with central updrafts are formed. These are called kolks, or boils, and are readily visible on the surface