Search notes:

DBA_COL_COMMENTS

dba_col_comments records comments for columns of tables and views.
Such comments can be stored with the comment SQL verb.
select
   column_name,
   comments
from
   dba_comments
where
   owner      = 'RENE'          and
   table_name = 'TAB_XYZ'
;

See also

Columns
Comments on tables are recorded in dba_tab_comments.
data dictionary

Index