1. The difference between the maximum and minimum of a given set of numbers; in a periodic process it is twice the amplitude, that is, the wave height. 2. The distance between two objects, usually an observation point and an object under observation. See slant range. 3. A maximum distance attributable to some process, as in visual range or the range of an aircraft. 4. The difference between high and low water in a tidal cycle. Ranges greater than 4 m are sometimes termed macrotidal and those less than 2 m are termed microtidal. Intermediate ranges are termed mesotidal. 5. In radar, lidar, and sodar, the radial distance measured outward from the location of the transmitter; ordinarily the distance to a target.