WordNet (r) 3.0 (2006):

Heaviside
    n 1: English physicist and electrical engineer who helped
         develop telegraphic and telephonic communications; in 1902
         (independent of A. E. Kennelly) he suggested the existence
         of an atmospheric layer that reflects radio waves back to
         earth (1850-1925) [syn: Heaviside, Oliver Heaviside]