Semi-ellipticals if a full spring is on each frame rail. Quarter-ellicticals if a "half"-spring is used on each frame rail. The Ford way is called transverse spring mounting.
If full length springs are used with one end mounted to the frame and the other with a shackle it's referred to as parallel leafs. If you use half a leaf spring on each side they are still parallel but would be called quarter elliptic springs. The FOGGER Pasadena beat me to it!
you mean paralell leaf? try this thread i started http://www.jalopyjournal.com/forum/showthread.php?t=399756