word is a measurement, calculation, counter, command, tag, function,
or other information entered into the frame position as a measurand.
measurand is a uniquely identified source (e.g., temperature of location
256, cabin pressure, fuel consumption obtained from an avionics bus,
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).