The Collaborative International Dictionary of English v.0.48:

Marconi \Mar*co"ni\, prop. a. [After Guglielmo Marconi (b.
   1874), Italian inventor.]
   Designating, or pert. to, Marconi's system of wireless
   telegraphy; as, Marconi aerial, coherer, station, system,
   etc. [archaic]
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Marconi
    n 1: Italian electrical engineer who invented wireless
         telegraphy and in 1901 transmitted radio signals across the
         Atlantic Ocean (1874-1937) [syn: Marconi, Guglielmo
         Marconi]