Higgs --- interactions and forces; distinction between these? At the moment I'm reading Lisa Randall's Knocking at Heavens Door, and I have a quick question that can no doubt be easily answered. I've often read and accept that there are four forces of Nature: Strong, Electromagnetic (EM), Weak and gravity. Forces are things that cause motion, and arise when charged (colour, ?, EM and massive) particles interact. Forces are a label for "interactions". Yet in discussing the interactions of matter with the Higgs field the "force" label seems not to be used; instead an unlabelled interaction is talked about, as in explaining the origin of mass. Why is the label "force" not used for this interaction, which in a sense is just an opposite sort of thing that prevents or obstructs motion by conferring inertia on matter?