yes it is the correct term. when anyone these days says Matrix they just think of the tile of a couple of films.
but a Matrix is a series of small units joined together to make one big unit, in the radiator there are dozens of small bore tubes that go from the top cavity to the bottom cavity (it's these that block up with debris). put enough in there it equals one big tube capable of allowing the fluid to flow freely from top to bottom.
if you think about it that is exactly the plot of the films, millions of human brains all connected to a super computer to create a imaginary world.