[OED]: 17. a. Physics. The area or space under the influence of, or within the range of, some agent; a state or situation in which a force is exerted on any objects of a particular kind (e.g. electric charges) that are present; the action of such a force; the value (or direction) at any point of the force on an object defined as having unit magnitude, or the set of the vectors that represent this force at each point in a region.