The Collaborative International Dictionary of English v.0.48:

Cockroach \Cock"roach\, n. [Sp. cucaracha.] (Zool.)
   An orthopterous insect of the genus Blatta, and allied
   genera.
   [1913 Webster]

   Note: The species are numerous, especially in hot countries.
         Those most commonly infesting houses in Europe and
         North America are Blatta orientalis, a large species
         often called black beetle, and the Croton bug
         (Blatta Germanica, formerly Ectobia Germanica),
         also called the German cockroach.
         [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

cockroach
    n 1: any of numerous chiefly nocturnal insects; some are
         domestic pests [syn: cockroach, roach]