Source : Webster's Revised Unabridged Dictionary (1913)

Metonymic \Met`o*nym"ic\, Metonymical \Met`o*nym"ic*al\, a. [See
   {Metonymy}.]
   Used by way of metonymy. -- {Met`o*nym"ic*al*ly}, adv.

Source : WordNet®

metonymical
     adj : using the name of one thing for that of another with which
           it is closely associated; "to say `he spent the evening
           reading Shakespeare' is metonymic because it
           substitutes the author himself for the author's works"
           [syn: {metonymic}]