x1 is a (set/pair) of scissors/shears/clippers/(hedge) trimmers/tongs [tool] with parts/blades x2 (scissor) and used for purpose x3
x1 is any whole tool composed of parts (blades, x2) which slide relative to one another, usually (but not necessarily) around a common pivot, so that little distance is between the blades. The blades need not close all the way nor do they need to be sharp or used for cutting(they could be used for grasping). Tongs typically are grasping-scissors, but tweezers are not. The emphasis is on how the blades move relative to one another and how they are connected to handles; the design is usually simple with only a few separate funtional parts. At least part of the blades should be to the side of the respective part of the other blade (so that these regions can move/slide relative to one another), even if the blades as a whole meet and cannot slide passed one another completely (such as with tongs). x1 is the whole object/tool, x2 are the parts which move relative to one another; in English, x1 could be called the "(pair of) scissors" whereas x2 could be called "the scissor (blade)".