A data word is a measurement, calculation, counter, command, tag, function, or other information entered into the frame position as a measurand. A measurand is a uniquely identified source (e.g., temperature of location 256, cabin pressure, fuel consumption obtained from an avionics bus, or a dump of the flight computer’s memory.) Each cell position in each frame contains the same measurand (subframes and embedded asynchronous frames may appear to be an exception, but are not; they are discussed later).