Depends on which table environment you are using. With tables and natural tables, \midaligned
centers the table:
\starttext
\midaligned
{\startTABLE
\NC A \NC B \NC C \NC \NR
\NC A \NC B \NC C \NC \NR
\NC A \NC B \NC C \NC \NR
\NC A \NC B \NC C \NC \NR
\stopTABLE}
\stoptext
or
\starttext
\midaligned
{\starttable[|l|l|l|]
\NC A \NC B \NC C \NC \AR
\NC A \NC B \NC C \NC \AR
\NC A \NC B \NC C \NC \AR
\stoptable}
\stoptext
There is no environment version of \midaligned
, but you can easily create your own if you want:
\def\startmidaligned
{\midaligned\bgroup}
\def\stopmidaligned
{\egroup}