Oh sure, you can call them whatever you like. But if you have an ADT system which has a unit type that isn&#x27;t quite the empty product then you&#x27;ll be in for an interesting time at least.<p>E.g., this is true in Haskell and it causes there to be some &quot;extra structure&quot; which often has to be smoothed over. Lots of library functions exist just to do this smoothing.