What is the definition of deep ocean currents?

A current deep in the ocean..... also they are caused by the density and how cold water sinking down the bottom and the warmer rising.... when this cycle happens it causes movement and creates a disturbance..... and then you have a deep ocean current wave!!! and if you are interested the wave only goes from like the middle of The Twilight Zone to the ocean floor.... In the middle when the cold and warm meet they start to mix... in my class room i remember an experiment that we did!!! we got three cups.. blue and red food coloring and we got water and put it in the cups...., one red, one blue and one clear.... when we poured the hotttt red water it rose up really fast and when we put the cold, blue water in it sank and ion the middle it was purple