"Curiouser and curiouser!" cried Alice. :)

context has two different versions of \define, there is one in syst-ext.mkii/syst-aux.mkiv which has no parameters but prevents you from overwriting a existing command (there \redefine with allows this) and another one in core-sys.mkii/mkiv which replace the first one and has support for parameters but replace on the other side the old definition (you get only the terminal message)

the question is, which behavious is correct, replace the old macro or keep it, in my opinion \define should leave the old definition untouced and \redefine should be used in this case (but we need a version with parameters)

-- Best Regards, Vyatcheslav Yatskovsky