Nomenclature can be considered as a type of synonyms.
 
Therefore, I can define a nomenclature as :
 
\definesynonyms[nomenclature][nomenclatures][\infull]

\setupsynonyms[nomenclature] [criterium=all,location=serried]

 

here I use location=serried, becasue I found the synonym is not in the same line ( higher than) the meaning.

 

But I want a three-column nomenclature list. The first column is the synonym, the second is the meaning, the third is the si-unit of it, if the synonym has an unit. Like

------

p             Pressure of xxx              Pa

l              Length of xxx                  m

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How to redefine the nomenclature command?