​You have plenty of choices:
​1- using predefined symbols, numbered 1 to 7 for usual itemation symbols:
\startitemize[4, columns, three, joindup, packed]

2- use alphanumeric symbols: A (capitals) a, R (romans), r
\startitemize[R, columns, three, joindup, packed]

3 - define your own symbol (like fontawesome symbols for checkbox for example)​

 
​


\setuppapersize[letter]
\starttext
  \startitemize[columns,joinedup,packed]
     \item ability
     \item absorb
     \item accuse
     \item act
     \item active
     \item actual
     \item adopt
     \item advantage
  \stopitemize
\stoptext

--------------------------------



Regards
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--
Dr YAHYAOUI Mohamed Kaddour, cardiologue -- Clinique KARDIA.