Draw an elongated rectangle. Make one of the long sides the runway. Fly up the runway and turn left or right. This short side is the CROSSWIND leg. Now turn to fly back down the other longer side parallel and opposite to the runway. This is the DOWNWIND leg. When you have passed the far end of the runway turn along the remaining short side of the rectange. This is the BASE leg. "Finally" turn to face up the runway again. This is the FINAL leg. That is the typical CIRCUIT around a runway, sometimes left-handed, sometimes right-handed and sometimes both!
Short final refers to a position somewhere along that FINAL leg.