Marmax was the first of the many suitors of Hippodamia. He and his mares were killed by Oenomaüs. His name would appear to derive from marmaros, 'marble' and anax, 'king', in its full form Marmaranax, 'the marble king'.
This was in fact the name of the white statue round which chariots were raced in the Hippodrome, so was almost a 'horse scarer', or at any rate 'one who rules the horses'. For Marmax such an interpretation can be regarded as propitious.